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Xibrari?
of tbe
mniverditi? of Midconein
1
V
THE ENGINEER SERIES
ELECTRIC WELDING AND
WELDING APPLIANCES
'' THE ENGINEER " SERIES
What Industry Owes to Chemical
Science. By Richard B. Pilchbr and
Frank Butler-Jonks, B. A. With an Intro-
duction by Sir George Bbilby» LL.D.,
F.R.S. Crown 8vo.
The Production and Treatment of
Vegetable Oils. By T. W. Chalmers,
B.Sc., A.M.I.Mech.E. Imperial 8vo. 9
Folding Plates, 95 Illustrations.
Paper Making and its Machinery.
By T. W. Chalmers. Imperial 8vo.
Illustrated.
Electric Welding and Welding
Appliances. By II. Carpmael. Imperial
8vo. Illustrated.
THE ENGINEER SERIES
ELECTRIC WELDING AND
WELDING APPLIANCES
BV
HERBERT CARPMAEL, A.M.Inst,C.E„ A.M.I.E.E,
(On the Editorial Staff of "The Engineer")
WITH 84 DRAWINGS AND
OTHER ILLUSTRATIONS
NEW YORK
D. VAN NOSTRAND COMPANY
1920
Printed in Great Britain.
.? 3 ?
8S
HPT —
5
: r. n n
Tl^H
.C?,'?>
G^'^^i^lt
PREFACE
The chapters which go to make up this book are reprints, — almost verbatim, the
editorial " we " even having been retained, — of articles which appeared in The Engineer
during the present year. The first was published on February 14th and the last on
August 29th.
To the average individual, perhaps, electric welding appears to be an outcome of
the War ; an expedient rendered necessary by the insistent demand for the speeding
up of production by all available means. As a matter of fact various processes of
welding by the aid of the electric current, notably carbon arc welding, have been in
commercial operation for a quarter of a century or more, this country having been
among the first to adopt and develop some of them. »Some of them, too, had, long
before the War, been much in vogue both on the Continent and in the United States
of America. In the case of the latter country electric welding had, for years before
the outbreak of hostilities, been most successfully resorted to for many purposes to a
considerable extent, especially for repair work on railway rolling stock. Sweden,
among countries ou this side of the Atlantic, may be cited as being in the forefront
in the employment of electric welding for ship repairing.
Nevertheless it is quite true that the War gave such an impetus to the use of the
newer method of welding as many years of endeavour during times of peace would have
failed to impart to it. Moreover, the War greatly enlarged the sphere of its application,
and was instrumental in bringing home to our manufacturers what a powerful agent
was the electric current for the carrying out of certain types of work. As a consequence
it has, nowadays, become the rule, rather than the exception, to find electric welding
plants in our factories, and there appears to be every probability of such plants being
even more extensively employed than they are at present. Furthermore, the War has
undoubtedly had the effect of developing and improving the machines and appUances
which both arc and resistance welding call for.
The central idea around which the articles were written for The Engineer was to
impart to the readers of that Journal a good general knowledge of the different
systems of electric welding which have been evolved and of the various machines and
pieces of apparatus which are required or are desirable for their efficient operation.
No attempt was made to go, in detail, into the history of the subject, though certain
historical matters are referred to. Nor was it sought to provide a handbook to the
subject by giving minute" instructions as to the correct manner in which to work the
various systems. To have done either, or both, would have entailed the introduction
of a vast amount of matter which would have resulted in the enlargement of the
volume to unwieldy dimensions, as well as in the production of a sense of weariness
in the mind of the reader, who, if he intends to adopt electric welding, in one or other
of its various forms, will naturally seek for practical instruction in the manner of
working it, which it is, of course, impossible adequately to convey in a book. Again,
it was considered undesirable to endeavour to enumerate, at length, the possible
viii PREFACE
applications of electric welding. Such an effort would have proved to be a futile task
since the number of such applications multiplies from day to day. Yet it will be
found that mention has been made of such a varied selection of applications as will
enable the reader to form a very fairly accurate conception of the wide area which has
already been covered.
It should be borne in mind that, though discovered in the middle eighties, and
though usefully employed ever since that time, electric welding, as a science, has
really, as yet, scarcely passed its infancy. It is very certain that the future — possibly
the very near future — will witness great developments in connection with it. Never-
theless, it does not appear to be likely that there will be any great fundamental
departure from the general principles, either of arc or resistance welding, which it has
been the endeavour of the author to deal with in this volume.
H.C.
LoNDOX, November, 1919.
CONTENTS
CHAPTER I TAOE
Introduction .............. I
CHAPTER II
The Benardos Carbon Arc Process ......... 8
CHAPTER III
Resistance Weirding ............ 14
CHAPTER IV
Arc Welding at a Steel Barrel Works . . - . . . . . .19
CHAPTER V
The Pontelec Methods and Machines ......... 25
CHAPTER VI
The Quasi-Arc Process ............ 33
CHAPTER VII
Resistance Welders of the British Insulated and Helsby Cables, Ltd. ... 31)
CHAPTER VIII
Machines and Apparatus for Arc Welding ........ 49
CHAPTER IX
Machines and Apparatus for Arc Welding icorUinued) ...... 58
CHAPTER X ..
Machines and Apparatus for Arc Welding (continti^d) ...... 65
CHAPTER XI
(1) Resistance Welders of the Electric Welding Co., Ltd. .... 75
(2) Some Large American ** Spot ** Welders ........ 78
CHAPTER XII
Oil-Drum-Making by Resistance Welding ........ 84
CHAPTER XIII
Resistance Welders of the A 1 Manufacturing Co., Ltd. ..... 89
\
X CONTEXTS
CHAPTER XIV
Thr Strknoth i)F Ki.ncTBir Welds , . . .
CHAPTER XV
A Laror BRmsH " Spot "-Weldiso Machine
CHAPTER XV [
The " Pijistic-Abc " Wkldinw System
CHAPTER XVII
The " A.C " System or Arc Wrldiso
Indrx
LIST OF ILLUSTRATIONS
FIG,
L
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
Helmet for Abc Welding
Examples of Welding (Benardos)
The Benardos Electrode Holder .
Device for ** Point *' Welding (Benardos)
The "Electric Forge" (Benardos) .
Device for Continuous or for *' Point " Welding (Benardos)
Suggested vFormation of Armour Plate (Benardos)
Diagram of Thomson Welding System
Diagram Showing Principle of ** Spot '* Welding
Diagram Showing Principle of " Seam " Welding
Diagram Showing ** Butt " Welding of Tyres
Joint Welded by Acetylene . . .
Carbon Electrode Holder (T. T. Heaton)
Welding-in the End of a Barrel .
Putting on Stiffening Ring to a Barrel
** Ponteleo " Resistance Welder
Machine for Brazing Collars on Tubes (" Pontelec ")
Spectacle-Frame Soldering Machine ("Pontelec'*)
Typical *' Pontelec " ** Spot *' Welder
** Spot " Welder for Bench Work (** Pontelec "}
" Pontelec " " Butt " Welder ....
Typical ** Pontelec " '* Seam " Welder .
Diagram Illustrating " Quasi- Arc " Welding
Welded Riveted Joint ......
B.I.W. " Butt " Welder, No. 57 ... .
B.I.W. Chain-Link-Forming Machine
B.LW. " Butt " Welder
B.LW. Chain Welder ......
]
30. > Examples of B.I.W. "Seam" Welders
:i
31
32. Group of B.I.W. No. 13 "Spot" Welders
33. Westinghouse Arc Welding Equipment on a Motor Lorry
34. Diagram of Connections of Westinghouse Generator for Arc Welding
36. Arrangement of Premier Electric Welding Co.'s Portable Welding Set
36. Premier Welding Set in Cabin
37. Portable Plant of the Premier Electric Welding Company
38. Lancashire Dynamo and Motor Co.'s Arc Welding Set
39. Connections of Lancashire Dynamo and Motor Co.'s Arc Welding Set
40. The Davies-Soames (Daysohms) Electro-Magnetic Differential Clutch
41. The' Davies-Soames Clutch Connecting a Motor to a Generator .
page
5
9
9
10
10
11
12
16
16
17
17
19
20
23
24
26
28
29
30
30
31
32
34
35
40
41
43
43
45
47
50
51
53
64
55
56
57
59
60
xu
LIST OF ILLUSTRATIONS
FIO.
42.
43.
44.
45.
46.
47.
48.
49.
60.
51.
52.
53.
54.
55.
56.
57.
58.
59.
60.
61.
62.
63.
64.
65.
66.
67.
68.
69.
70.
71.
72.
73.
74.
75.
76.
77.
78.
79.
80.
81.
82.
83.
Hi.
Davies-Soame8 Clutch arranged for Arc Welding
Diagram of Connections of Davies-Soames Clutch
Electric Connections of " Constant-Energy " Balancer Set
Holmes Portable Generating Set for Arc Welding
Holmes Resistance Frame for Arc Welding .
Tillino-Stevens Lorry equipped for Arc Welding
Tilling-Stevens Arc Welding Lorry — Interior
Tilling-Stevens Arc Welding Lorry — Driver's Seat
Tillino-Stevens Arc Welding Lorry
Crompton Self-Contained Arc Welding Set .
Crompton Motor Generator Set for Arc Welding
Equipment and Engineering Co.'s Electrode Holders
Electric Welding Co. — ** Butt " Welder for Tubes, Rods, etc.
Electric Welding Co. — " Butt " Welder with Radial Welding Blocks
Electric Welding Co. — ** Butt " Welder for Miscellaneous Repair Work
Electric Welding Co. — " Butt " Welder for Strips, etc.
Electric Welding Co. — " Butt " Welder for Hoops, Rings, etc
American " Spot " Welder for Ship Work
Large American Duplex " Spot " Welder
Electrical Arrangements of Dltlex Welder
" A 1 " " Spot " Welder .
** A 1 " Automatic Switch
" A 1 " ** Butt " Welder .
" A 1 " " Butt " Welding Attachment
" A 1 " " Se^m " Welding Attachment
Welded and Riveted Joints .
Large *' Pontelec " ** Spot " Welder, with Stakes arranged Horizontally
Large ** Pontelec " " Spot " Welder, with Stakes arranged Vertically
Large ** Pontelec " " Spot " Welder — Upper and Lower Stakes or Arms
Large " Pontelec " " Spot " Welder — Arrangement of Electrode Slide
Large ** Pontelec " ** Spot '* Welder — Arrangement of Transformer
S.S. Oeorge Washington — Fractured Circulating-Pump Casing
S.S. Prim Joachim — Broken Cylinder-Head and Broken Low-Pressure Cylinder
S.S. Kaiser Wilhelm II — Fractured Low-Pressure Cylinder Liner
S.S. Friedrich der C/rcw«c— Broken Steam Intake, Second Intermediate Cylinder
" Plastic- Arc " Welding and Cutting Panel ......
** I*lahtic-Arc " Welding and Cutting Panel, Electrical Connections .
Cracked Loc()mc)Tive Frame — Early Stage of Repair by Arc Welding
Cra<'Kki) Locomotive Frame -Final Appearance of Repair by Arc Welding
The " A.('." Klkctiuc Welding and Cutting Machine ....
Mkthodh ok ('onnecting up the *' A.C. " Machines with Different Types of
' < I RO 1 ' I Tn .••*.•....
The **A.('." Electrode Holder ......
The ** A.C." Ele(;trodk Holder Gripped to Release Electrode
'ri
PAGE
61
02
63
66
67
68
69
70
71
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73
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lOi
105
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120
!{■■
I '
I I
l«
CHAPTER I
INTRODUCTION
Electric welding, which is far from being a novelty, has recently come prominently
into public notice. It has not only been employed by the Admiralty for the con-
struction of vessels, but Lloyd's Register has issued regulations under which it is
prepared to sanction its use in shipbuilding operations generally. Moreover, the
astonishing rapidity with which the damaged interned German liners were repaired
by this process, thus enabling many thousands of American soldiers to be brought
to Europe long before such transportation was deemed to be possible, is stiU fresh in
the public memory. We feel sure, therefore, that a discussion of the subject will be of
interest to our readers, and we propose in the present and succeeding chapters to
deal with the question at some length. No attempt will be made to go in detail into
the evolution of the various processes involved, our purpose being, rather, to show
1 what has been and is being done, than to relate exactly who was the inventor of this
and who was the discoverer of that. It will suffice to say that, quite early in the use
of electric energy, experiments with a view to using the current for welding purposes
were instituted, and that thirty years and more ago electric welding was practised
notably by that prolific inventor and distinguished investigator, Elihu Thomson, and
by the Russian Benardos. Of the work of these two men we shall have much to say,
but we shall not attempt to deal with it exhaustively, so that what follows in no way
claims to be a complete history of their discoveries, nor, indeed, of electric welding
as a whole. It is noteworthy that though introduced at no widely diflEering periods of
time the methods of Thomson and Benardos were entirely dissimilar, the one employing
what is termed the resistance process and the other the arc process. All the electric
welding systems in use at the present day may be classed under one or other of these
two heads, though there are numerous variations in the application of the two
principles.
Resistance welding resembles much more closely the original welding of the black-
smith than does arc welding ; indeed, saving that the manner of arriving at welding
heat is difEerent in the two cases, the welding of the gimithy is identical with the welding
by the resistance method. In both the portions of the parts to be joined together
are raised to a proper heat in the immediate neighbourhood of the proposed weld,
and then welding is eflfected either by means of pressure or by percussion. The same
precautions regarding the cleanness of the surfaces to be joined together have to be
exercised in each case. Arc welding is essentially different in that the metal is in the
majority of cases actually melted at the weld, and that neither pressure nor hammering
is absolutely necessary, though in some cases, they may be beneficially applied. As
we shall show, however, there are cases in which the arc is used simply to obtain
welding heat. In such instances, of course, percussion or pressure is required to con-
solidate the welds. Both arc and resistance welding are being more and more exten-
sively employed and, from present indications, it would appear highly probable that
both will continue in vogue, since each has its own sphere of usefulness, in which it
performs with better effect than does the other. Nor does it seem likely that either
1E.W. B
2 ELECTRIC WELDING AND WELDING APPLIANCES
will oust the acetylene method, which likewise iB^re-eminent in certain directions ;
£0 that the engineer of the present day is fortunate in having three more methods by
which welding can be effected than had his predecessor of the last generation. It may
be even said that he has more than that if the oxy-hydrogen or oxy-coal.gas methods
be taken into account.
In both resistance and arc welding a certain amount of special machinery or ap-
paratus is required, though with the latter it is generally less elaborate than with the
former. For resistance welding alternating current is almost universally employed
in practice, though there is no reason why direct current should not be used, saving
the difficulty of dealing with the heavy currents. In arc welding, on the other hand,
either direct or alternating current can, under certain circumstances, be employed,
though direct current is most generally used. Resistance welding may be effected by
three methods : — (a) Butt welding ; (6) spot welding ; and (c) line or seam welding,
together with several modifications. Arc welding may be performed either with bare
metal electrodes, with flux-covered metal electrodes, or with carbon electrodes.
The quality of the current — ^if such an expression be permitted — employed in the
two processes differs very widely. In resistance welding there must always be a very
heavy current — in some cases it amounts to thousands of amperes — and a very low
pressure, say, from J to 6 volts. Some largo machines have recently been built in
America in which voltages considerably in excess of the higher of these figures have
been employed. We shall refer to them later. In arc welding, on the other hand, the
voltage ^must always be high enough to maintain an arc — say, from 20 to 56 volts —
and the current is relatively small. As a matter of fact, it is found in practice that the
electromotive force available should, at any rate with metal electrodes, be at least
from 60 to 75 volts, while some processes require an available pressure of from 100 to
110 volts.* With carbon electrodes a pressure of 90 volts is commonly employed.
The current in arc welding is adapted to the nature of the work being carried out.
It may be quite small, say, from 15 to 20 amperes, and it is very rarely, we believe,
that it exceeds 800 amperes with carbon electrodes, and less than half that with metal
electrodes, the average in actual practice being considerably less than the smaller
figure. In the arc process, as originally introduced by Benardos, the work which was
to be welded was connected to the negative terminal of a source of electrical energy —
in the first instance storage batteries were employed — while the positive terminal was
connected to the carbon electrode. An arc was formed by touching the work with the
electrode and quickly withdrawing the latter, the result being that the metal im-
mediately adjacent to the point of impingement of the arc was quickly raised to a very
high temperature, and a stick of similar metal could also be melted just over the spot
much in the same manner as solder is melted with a soldering iron. Later, this arrange-
ment was found to possess the disadvantage that, as the direction of the current was
from the electrode to the work, there was a tendency for the carbon, either in the form
of vapour or in minute highly heated particles, to be carried over to the latter, so that
it entered into combination with the molten metal, and sometimes, undesirably
altered its composition. Hence the polarity of the work and electrode were inter-
changed, the former becoming the positive and the latter the negative. A further
reason is put forward by the advocates of the carbon arc process as to why the work,
and not the metal electrode, should be made the positive terminal, and that is that
the positive terminal of an electric arc is hotter than the negative terminal. We
believe we are right in stating that carbon arc welding was first employed commer-
♦ It will be found in a subsequent chapter that this statement is modified. The tendency would appear
to be to reduce the voltage.
I
INTRODUCTION 3
ciaUy in this country by the firm of Uoyd and Uoyd, of Birmingham, which is now
merged in the firm of Stewarts and Lloyd. It has also been used with success, for twenty
years or more, by the Steel Barrel Co., Limited, of Uxbridge.
Some ten years after this introduction of the Benardos process the idea occurred
to another Russian — Slavianoff — ^to employ a metal electrode instead of a stick of
carbon, his idea being to fill up blowholes in defective castings. Previously Benardos
had suggested the employment of a cored carbon, the core consisting of metal. Whether
such composite electrodes had any great vogue' we are unable to say, but having re-
gard to latter-day developments in coated electrodes the suggestion coming, as it
did, as far back as the year 1885, is distinctly interesting. Covered metal rods are, as
we shall show later, in very extensive use at the present day, but the covering is not
carbon ; indeed it is, for the most part, a non-conductor. It is interesting to note
that in 189*3 — some two years before Slavianoff introduced the use of metallic elec-
trodes — Mr. T. T. Heaton, of the Steel Barrel Company, Limited, had suggested a
mild steel electrode to the late Mr. Dickinson, of the Bowling Iron Company, and
that it was tried, though without success, the experiment not being persevered with.
The Slavianoff method ha^, of recent years, been very considerably developed, and
though it would be erroneous to imagine that the metal electrode has entirely displaced
the carbon electrode, for it has done nothing of the kind, yet it is safe, we beUeve,
to say that in the large majority of welding installations in which the arc process is
employed, metal electrodes of one kind or another are used.
A development of the carbon arc process is that in which the arc is struck between
two carbon rods arranged at an angle to one another, the angle pointing downwards.
By means of an electro-magnet arranged between the carbons, the arc is projected
downwards on to the work. The device is cumbersome and not particularly easy to
' ^PP^y> ^0 ^^^^ ^^ ^^ hardly surprising that it has not come largely into use, though there
would appear to be no reason why it should not do its work perfectly well. In the only
example we have seen, the arrangement was such as we have described above, and the
whole apparatus was suspended from a hook. It was not, therefore, possible to use
it for vertical or overhead work. Its invention is attributed to Zerener, of Leipzig,
and, to the best of our knowledge, the system is only in operation in Germany, and
only there to a quite limited extent.
For arc welding the special appliances actually necessary are but few. In addition
to the source of electric current and the electrode with its holder, all that is essential
is a steadying resistance, connected in series with the arc, and possibly an ammeter
as weU. As will be seen later, however, Special machines have been introduced with
the purpose of preventing rushes of current. It will be readily understood that, unless
means for controlling the current are employed, a resistance, or some such device,
in series with the arc is an absolute necessity, for without it when the electrode touches
the work there is a complete short circuit until the arc is struck. Although, however,
but few special appliances are required, it is generally found that the supply of current
available is not suitable for welding. For instance, it is very rare nowadays to find
a pubUc supply with as low a voltage as even 1 10. Hence it is necessary,, if the current
be not specially generated, to reduce the pressure so that there may not be an
excessive waste of energy in the resistance. If the current be alternating the reduc-
tion in pressure is readily effected by means of a static transformer, which may have
different tappings in the primary, so that different voltages and currents to suit
different kinds of work may be obtained. This arrangement, of course, applies only
if alternating current is to be employed in the arc. As a matter of fact, direct current
is, as we have said, almost universally used, at any rate in this country, and to pro-
4 ELECTRIC WELDING AND WELDING APPLIANCES
duce the low voltage direct current a motor generator may be employed. The
direct cmrent half of motor generators designed for arc welding are ordinarily com-
pound wound, and are preferably provided with commutating poles, so that sparking
may be minimised. The size of machine required depends, naturally, upon the
nature and amount of the Work being carried out. The variation in the. current
when using metallic electrodes may be between, gay, 15 and 250. These may be
regarded as extremes, only met with in special cases, the more usual range
experienced in actual practice being between, say, 20 and 200 amperes. With
carbon electrodes, on the other hand, much heavier currents are experienced. We
understand that satisfactory results cannot be looked for with currents under
300 ampdres, and that not infrequently 500 and in special cases as many as
800 amperes may be required. With these figures an estimate may be arrived
at regarding the capacity of the machine necessary for any given number of
welders.
At this point, perhaps, a few words may be said with regard to the arc itself and
its eflfects on the human frame. In the first place, the arc with a carbon electrode is
long and the temperature in the positive crater is very high. In a paper which he read
.before the Institution of Engineers and Shipbuilders, in Scotland, on June the 22nd,
1918, Captain James Caldwell, R.E., Deputy Assistant Director of Materials and
Priority, stated that it was estimated to be 7600 deg. Fah. It is not, a6 Captain Cald-
well explains, necessary to reach such a temperature as this in welding, and the carbon
rod is therefore moved along at a rate which will ensure good furion to the necessary
depth. With metal electrodes, partly because of the shorter arc and partly because
of the pressure of the vapour of the metal, it is lower but still high. In both cases, and
particularly in the former, ultra-violet rays are freely emitted. The eifect of exposing
the eyes, face, and hands to direct rays from the arc is very similar to severe sunburn,
such as is familiar to climbers in high altitudes on freshly fallen snow. The results
of being burnt in this manner by careless exposure are exceedingly painful, and
whereas there are those who say that no permanent injury is caused to the eyes of
operatives constantly engaged in electric welding, there are also those who aver that
cataract may result in cases of careless exposure. However, with reasonable care
and with proper precautions, there need not, apparently, be any ill-effects whatever.
It is necessary, however, adequately to shield not only the eyes but the face and neck
as well, and, of course, the hands. In some cases screens sufficiently large to protect
both the head and neck are employed, the screens being furnished with glasses of colours
of such a character that while the harmful rays are cut off the operator can readily
see what he is doing, at any rate when the welding is actually in progress. Then, too,
aluminium helmets, or cylinders, put on over the head and resting on the shoulders,
are used. An example of a helmet which is being employed in some shipyards is shown
in Fig. 1. It will be observed that the protective glasses can be raised when required
so as to give the operator unobscured vision. It is customary also for heavy leather
gauntlets to be worn so that both hands and wrists may be protected, and, though
ordinarily the clothing is sufficiently thick to give protection to the body, it is the
wisest course to wear a leather apron, reaching down to the boots, for splashes of metal,
and, when coated electrodes are used, of molten slag, may be projected from the arc.
Coat-sleeves must, in no case, be rolled up so as to expose the forearms. These precau-
tions may sound formidable, but in reality they are not so, and in order to ensure
immunity from injury, which may be exceedingly painful if it be nothing worse, it
is imperative to take them. Further than this, it is most desirable that any workshop
or compartment in which arc welding is in progress should be adequately ventilated.
INTRODUCTION 6
The fumes somotiniea given off are offensive, and if not carried away as fonned may
injure the health of the operatives.
It is important, too, that the colours of the glass screens should be such that they
entirely absorb all the ultra-violet rays. Certain combinations of blue and deep red
glass will effect this absorption. So will glass having a greenish amber tint, and this
colour is, we gather, largely used in the United 8tat«s. There ore other glasses, too,
for which it ia claimed that they are impervious to ultra-violet rays. We shall have
more to say regarding this matter in a later chapter.
There is a great deal of difference of opinion as to whether or not in arc welding
a flux IS necessary. There are those who allege that, whereas it is not required with
metal electrodes, it is most desirable when carbon electrodes are used, since it enters
into combination with any carbon which may be projected in the direction of the
Fio. 1. — Helmet for Arc Welding,
weld and prevents it combining with the metal. Then, again, there are those who
maintain that a flux is necessary to increase the fluidity of the metal. It is urged,
too, that welding by means of the carbon arc without a flux results in the fonnation
of a crater of boiling metal, which greedily absorbs oxygen from the atmosphere, and
that a weld which has absorbed oxygen will always be weak, because the oxygen will
react and combine with the carbon in the metal, and with the metal itself, and the
metal becomes poroug. The same allegations are made regarding the use of metal
electrodes without flux. Into this controversy we do not, at the moment, propose to
enter ; nor do we propose to discuss the relative merits of bare and coated electrodes.
Each has its own advocates. In the United States bare electrodes were, as we have said,
almost exclusively employed up to within quite a short time ago ; whereas, in this
country covered metal electrodes have been most extensively used. In both countries
a large amount of excellent work has been carried out, and we are not prepared, with
our present knowledge, to adjudicate between the two methods. It is significant,
however, that in the case of the electrically welded bai^e, to which we made reference
in our issue of August 9th 19IS, and work on which was carried out under the supw-
6 ELECTRIC WELDING AXD WELDING APPLIANCES
intendence of the Admiralty authorities, and under the eyes of experts from lioyd^s,
metal electrodes, provided with a special slag-forming coating, were exclusively used.
It is noteworthy, too, that coated electrodes are much more frequently used in the
United States nowadays than they used to be. It is also an undoubted fact that
excellent work can be and is constantly being done with the carbon arc on mild steel
without the use of any flux whatever. The question is rendered all the more difficult
i^ that there is no sort of agreement as to the composition of the flux or the flux-
forming coating which it is best to employ, and because an excessive current in the
arc may bring about a condition in the weld which is very similar to, if not actually
identical with, that stated to be caused by the use of, say, a carbon electrode without
a flux. The only point on which there seems to be no divided opinion is that if a flux
is to be used, the most convenient method of applying it is to coat the electrode evenly
with it. One authority on the subject states, with regard to this point : "When
appUed in this way the coating may be made to serve two useful purposes, providing
it contains sufficient refractory material : (1) It permits the electro-magnetic effect
of the welding current to act upon the molten metals ; and (2) it appUes flux to the
weld at the rate that adjusts itself perfectly to that of the melting of the welding
penciL"
It should be mentioned, however, that all the coatings applied to metal electrodes
are not flux forming, or, we should more correctly say, Uquid flux forming. In what
is known as the "gaseous flux process,'* which was introduced and patented by
Kjellberg, the metal electrode is — ^again to quote Captain Caldwell — " covered with
a fireproof sleeve of non-conducting material, so that as the metal is removed by the
arc the sleeve projects beyond the end of the rod and forms a guide for the molten
welding metal, the sleeve itself falling away automatically. The sleeve protects the
metal from oxidation and reduces heat losses." ** The process," continues Captain
Cakiwell, " is an improvement on the bare metal electrode, and a great deal of satis-
factory work has been done with it, mainly in repairing marine boilers, stem frames,
and other ship parts. It is also successfully used to build up worn parts, such as
propeller shafts, worn crank shafts and axles, which are afterwards machined to
size. The patent specification claims the use of no particular material for the fire-
proof sleeve, and no other purposes than those mentioned, but the company ex-
ploiting the process states that the sleeve can be made the vehicle for constituents
which will give desired characteristics to the added metal." The arc actually dissi-
pates the flux, so that no slag is formed.
It is not to be supposed that electric welding will always produce work which is free
from defects, for that is not the case, and unfortunately, it is by no means always that
a defect, should it exist, can be detected, even by careful observation from the outside.
In resistance welding some foreign matter may have got between the surfaces being
operated upon and have reduced the area properly welded. In metal arc welding,
if the operator has used too smaU a current, or held the electrode too far away from
the work, the melting of the edges of the work may not have been properly effected,
so that there is not adequate adhesion between them and the added metal. The joint,
to outside appearance, may look all right, but there may be cracks between the work
and the added metal which will, in time, certainly lead to trouble. An excess of current,
on the other hand, will have the effect of what is known as " bad metal " being de-
posited. Then, again, bubbles of gas may form in the weld, and hence reduce its
strength. It is quite possible, too, when using a carbon arc incorrectly, to burn the
metal by using too heavy a current or by keeping the arc playing on one particular
spot for too long a time. However, it is by no means always that a perfect wel<J is
INTRODUCTION 7
obtained, either by the blacksmith or by the use of the acetylene torch, and it is prob-
ably accurate to say that, with arc welding at any rate, the proportion of imperfect
welds on any given piece of work made by even a comparatively unskilled worker, is
as small as, if it be not smaller, than is the case with any other welding process. More-
over, there is no reason to suppose that when reasonable care has been taken resist-
ance welding produces — ^in general practice — ^welds which are inferior to those
obtained by the smith, and it certainly can do work which he cannot carry out.
We shall have more to say regarding the strength of electric welds in a later
Chapter.* I
♦ See Chapter XIV.
CHAPTER II
THE BENARDOS CARBON ARC PROCESS
As we said in our first chapter, this series is by uo means intended to constitute a
history of electric welding. To have attempted to make it do so would have intro-
duced an immensity of weary details, and made the whole thing unwieldy. Hence,
we shall not discuss the claim made for Benardos that he invented arc welding, further
than to say that there are those who allege that de Meritens, whose pupil Benardos
was, was the actual discoverer of the arc welding process. On this point we shall
not make any definite assertion ; nor is it neoessary for our present purpose to do so.
It can be truthfully said, however, that the Russian was largely instnimental in
bringing the subject to pubUc notice, and that in 1885 he, in conjunction with a fellow
countryman of his, one Stanilaus Olszewski, an engineer of St. Petersburg, obtained
a British patent — ^No. 12,984 of that year — ^in which the first claim read as follows :
" The method substantially ad herein described of uniting and soldering metals together,
either at separate points or in a continuous joint by heating them by means of an
electric current," and that the methods described embodied the employment of the
carbon arc. It would be interesting to inquire into the question of how much of the
invention was due to the one inventor and how much to the other. Nicholas de
Benardos is described in the patent specification as ^' Gentleman," his partner, as
we have said, as an engineer. What part did he, whose name has alone survived as
being coupled with the invention, actually play in the discovery ? This, again,
is a point which we shall leave to others to discuss, and shall confiine ourselves to giving
certain extracts from the specification, which is certainly a most comprehensive
document.
The invention is described at the outset as relating to ^'an improved method of
and apparatus for the direct application of electric currents for the following purposes :
1. The union of metals.
2. Their disunion or separation.
3. The formation of apertures in metals. .
4. The union of metals in layers.
The process, which we term eleotrohephaest, consists of the formation of voltaic arcs
when necessary." It is explained that the voltaic arc is formed by the approach
of carbon — or any other body sertnng the purpose, the italics are ours — to the part of
the metal to be operated upon, the carbon forming one pole of the circuit and the
metal the other pole.
It is curious what wide area of ground is covered and how many are the uses to
which the inventors claim that their invention can be put. It is pointed out in the
first place that the union of parts of one or more kinds of metal may be effected in two
ways, namely, "either in points or continuously: 1. In points by agitating the
voltaic arc at one point for a certain time, after which it ceases ; 2, continuously,
in which case the voltaic arc advances uninterruptedly in a defined line. In both
THE BENARDOS CARBON ARC PROCESS &
cases, the union or cohesion of the parts is simultaneous, and they become one homo-
geneous whole." One is at once struck with the similarity between the processes
described and present-day spot and seam welding, though nowadays spot welding,
at any rate, is almost invariably, if not universally efiEscted by the resistance process,
and many kinds of seam welding are only practicable by the latter method. " Point
union," the inventors declare to be " in svery way superior to riveting," while " Con-
tinuous union " is also described as superseding riveting, "particularly in the case
of boiler joints, etc., and is generally applicable in all cases of joining or uniting metals."
A variety of different methods of making joints in iUustrated. Among them is a
joint formed between two plates by welding the slightly projecting ends of headless
rivets, and another in which only one of the plates has holes drilled in it, and the joint
is effected by filling up the holes with ,
melted metal which itself becomes
welded to the metal of the imperforated
sheet. Sketches roughly illustrating
these two methods of jointing are
shown in Fig. 2. Presumably, hammer-
ing was re&orted to in order to con-
solidate the weld, as is indicated in the ' "" """"pi^^ 2.-Ei«mple8 ot Wdding.
right-hand joint in each case, but
hammering is not actually mentioned in connection with joints of this type, though
the utility of hammering or pressing was fully understood by the inventors, as we
shall show later.
The inventors were not backward in praising their process, as is amply evident
from the following extract, which is taken from that part of the specification which
immediately follows the reference to jointing : " As compared with existing processes,
the advantages claimed for the present invention are its rapid action, cheapness, the
reduction in weight owing to the absence of joints, cover joints and heads of rivets.
By this process the strength of the joints becomes equal to that of other parts of the
objecf, which is most important in boiler and armour plate, iron and steel vessels,
hydrauhc apparatus, etc., and had hitherto been attained with great difficulty. Besides
the advantages above enumerated, the great feature of our invention consists in the
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facility with which it can be applied on the spot in cases of emergency or accident
without taking the object to pieces : as, for instance, in the case of the bursting of
boiler plates, the cracking of armour plates, etc."
The carbon electrodes which might be used are referred to as being of various forms,
10
ELECTRIC WELDING AND WELDING APPLIANCES
the mo8t practical for operations on a small scale being ^' either a solid or hollow pencil
or rod. The hollow carbon is filled "with various metals or their alloys, which play the
part of solder." To this we shall refer again later. Of holders, various forms are
LUustrated. The simplest is very similar to that in u^e at the present time. It is shown
in Fig. 3. The hollow at the end of the wooden handle contains a contact screw which
Fig. 4.— Device for "Point" Welding.
serves to fix the wire of the conductor, while the electrode consists of a carbon pencil
held in a tube by means of a screw. This carbon-containing tube works on a hinge, and
may at the will of the operator assume ^^arious inclinations with regard to the lever
which connects the conductor with the carbon. A more complicated arrangement.
Swain Sc
Fig. 5. —The "Electric Forge."
which is specially intended for use in " point " welding, is shown in Fig. 4, which
gives a cide view of the apparatus. It is, as will be observed, furnished with a, lever
or trigger for pressing the carbon down to the point where the arc is to be formed, this
motion being accomplished by simply pressing the lever. The breaking of the arc is
THE BENARDOS CARBON ARC PROCESS 11
effected when tlie pressure on the trigger ia removed by the action of a spring pressing
against the trigger, tending to force it downwards. The conductor is fixed to a contact
post contained in the handle of the lever. A still more complicated device is shown in
Fig. 6. It is intended for use either in " point " or continuous welding, and is furnished
with a protecting screen and also a stop watch, which was started by the some
mechanism which struck the arc, so that the observer might see how long the current
had been at work. When it was to be used for continuous welding, the rails, on which
the apparatus ran on wheels, were to bo of the ordinary plain topped type, but when
employed for "point " welding one of the rails was to be corrugated, the distance
between the corrugations determining the distance apart of the welds.
Reference may also be made to Fig. 5, which shows what the patentees called an
" Electric foi^e." It consists of an anvil carrying a bracket, furnished with a pulley,
Fid. 6. — Device for Continuous or for "Point" Welding.
to which is attached a pair of tongs for holding the object to be operated upon. The
carbon is arranged on a stand to which is fastened one conductor leading to the source
of current. The other conductor, which is attached to the anvil, is in electrical contact
with the object to be heated. When the latter is touched on the carbon electrode and
withdrawn, an arc is formed, the object is heated and is then transferred to the anvil
for forging.
By their process the inventors claimed that fusion of layers of metal one on top
of the other might be brought about by introducing into the arc a " carbon pencil
prepared with the metal with which the fusion is to be effected, which falls drop by
drop in a continuous jet. The pencil is insulated. . . . This process can be employed
in a number of cases for soldering, for filling up flaws, cracks, hollows, etc., moreover it
can be applied for steelifying objects for makii^; stayB, supports, etc." By steehfying
the inventors intended to convey, we take it, hardening or tempering. The use of the
arc for making holes is claimed and so is " the separation and disunion of metal," or
as we call it nowadays, simply " cutting." " Farts of metal of considerable dimensions
12
ELECTRIC WELDING AND WELDING APPUANCES
may," says the specification, "be detached by this process with facility on the spot.
The tension and quantity of the electric current must be increased in proportion to
the size of the metal operated upon. Numerous cases occur where the separation or
detachment of metallic part^ cannot be effected by eidsting means, and which could
be easily accomplished by our process."
One of the most curious claims made for the process was, however, its use for the
formation of armour plates. The resulting product is shown in Fig. 7. The steel
plates were to be joined together both by point and continuous union. They were to be
laid one on the top of the other, with intermediate layers of some elastic substance
such, for instance, as caoutchouc, felt, cardboard, wood, etc. The elastic substance
is shown in the drawing by shading. The inventors point out that these armour
plates might serve for protecting vesselsl and for numerous other purposes ; that they
are exceedingly light, offer great resistance, are not hable to crack and split, and that
they may, with great facility, be made on the spot where they are to be used, either
whole or attached layer by layer when they are being mounted.
The inventors evidently realised that in some of the processes carried out in
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accordance with their invention, consolidation of the welds would be necessary,
for they state that the apparatus described " can also be directly connected with'other
instruments, as, for instance, with the rolls, stamping press and automatic hammer
to which the metal is automatically conducted on the cessation of the arc, for the
purpose of further cohesion and final planning." They were also aware of the necessity
for protecting the eyes of the user, for they explain that the various pieces of apparatus
described are fitted with " Coloured glass screens or some similar substance, so as to
allow of the operation being watched without injury to the eyesight of the operator.
We give one further extract from this interesting document : " This process of
working metals may be combined with a gas apparatus, whereby gas or a mixture of
gases could be introduced by pipes into the voltaic arc, and increase its tension. Into
these gases may be introduced pulverised carbon, which is a good conductor of elec-
tricity, and also increases the action of the voltaic arc. If it be necessary to fuse any
heterogeneous substance with the metal operated upon, the carbon may be replaced
by any other substance in powder."
It must be admitted that this specification, the date of which, it should be remem-
bered, is 1885, very nearly covers the whole sphere of electric welding as it is now
practised. Butt welding, spot welding, seam welding, and the building-up process
THE BENARDOS CARBON. ARC PROCESS 13
are all of them either mentioned by name or shown in the illustrations. It is true that
the specification had to be amended in 1891, but none of the points which were excised
in the emendation, have been referred to in the foregoing. It is quite clear that it was
foreseen that electric welding was bound to assume a very important position in engin-
eering construction, and it is a matter for wonder that, though in several outstanding
examples the process has been successfully employed commercially for getting on for a
quarter of a century, it is only comparatively recently that it has in any sense been
widely used. It is not so very long ago that the Admiralty refused to permit the use
of electrically welded tanks, though it has now definitely relinquished that position.
Moreover, as showing the trend of feeling in other directions,* we may say that we
have before us a copy of the railway companies' specification for iron or steel drums,
suitable for the conveyance of acetone, acetone oils, ketone oils, coal tar, naphtha,
benzole, toluol, turpentine substitutes, xytol, mineral naphtha, petroleum, benzine,
benzoline, carburine, motor spirit and petrol, in which it is set out that not only
must all the joints be electrically welded, but that each drum must also be provided
with a well-fitting screw bung, the boss of which must be electrically welded to the
head of the drum.
CHAPTER III
RESISTANCE WELDING
Resistance welding, like many other valuable inventions, was discovered by accident.
As it happened, too, the discovery of the process came at a most opportune time, for
early makers of dynamos were seriously handicapped by the fact that the wire manu-
facturers could not or would not supply the insulated wire in sufficient lengths. It
was impossible to wind even a comparatively small coil without having to make one
or more joints in it. These joints had to be brazed or silver soldered by means of a
blow-pipe and then insulated by taping-up, with the result that the wire was con-
siderably thicker at the joints than elsewhere. The extra thickness made the winding
of a really neat coil a. matter of great difficulty, and the wire makers were urged again
and again to make the joints in the first place before applying the insulation. Among
those who endeavoured unsuccessfully to get them to do so was Professor Elihu
Thomson, who was then (about the year 1885) connected with the Thomson-Houston
Electric Company, of Lynn. The reply he got was that what he suggested was im-
possible by any method known at the time. However, he himself was destined to
discover a means by which the joints could be easily and efficiently made, and the
story of how he came to do so was told in the following words by Mr. J. B. Clapper,
plant engineer of the Rim and Tube Division of the Standard Parts Company,
Cleveland, Ohio, in a paper which he read before the Cleveland Engineering Society,
on March 26th, 1918.
" While giving a lecture on electricity in general at the Franklin Institute of
Philadelphia, one evening, among other apparatus for demonstration purposes, Prof.
Thomson had with him a large high-tension jump spark coil and also some Leyden
jars. After showing how a long spark could be produced from the secondary terminals
of this coil by applying an interrupted direct current at the primary terminals, he
then thought of trying an experiment with this coil the other way around. Accordingly,
he arranged for one of his assistants to discharge several of the Leyden jars in series —
thereby effecting a very high potential — through the secondary winding of the spark
coil, while he held two wires together, end to end, which were connected across the
primary terminals of the coil. After discharging the jars in this manner, the Professor
found that he could not pull the wires apart that he held — ^they had become joined
at the ends through the heating effect of the current passed through them — in short,
the first electric weld had been made quite unintentionally. However, since the wires
that the Professor held in his hands were copper, it immediately dawned on him —
here was his solution to joining two lengths of copper wire together— electric welding."
The Professor, being a business man as well as a distinguished scientist, at once
decided to put his invention on a commercial footing. He patented the invention,
and the first practical machine which he designed was known as the " Jews' Harp
Welder." It was the parent of the very many different machines which are now
employed for applying resistance welding for a large number of different purposes.
In it, according to Mr. Clapper, the secondary winding was solid and of U form, the
metal being thinned in cross section at the bottom of the U so that the ends on which
RESISTANCE WELDING 15
the clamps for holding the ends of the wire to, be welded were mounted could be
moved together or ap&rt enough to permit pushing up the stock in welding. The
primary winding was a circular coil of many turns, laid within the secondary, which
is said to have exactly resembled a Jews' harp in shape. The core consisted of many
turns of iron wire wound '^ around and through the primary coil, embracing the
secondary for its portion immediately adjacent to the primary winding." The pressure
on the work was effected by a spring, tending to draw the outer ends of the secondary
together, the tension being varied by a hand-operated screw passing through the
spring. In 1888 the Thomson Electric Welding Company was formed commerciaUy
to develop, manufacture and put on the market apparatus for adapting the Thomson
process of welding to all lines of business coming within its scope.
The original application of resistance welding was thus to the joining together of
lengths of copper wire. It very soon, however, came to be used not only for iron and
steel, but also for brass, aluminium and the finer metals, and how wide is the range
of its applications nowadays may be gauged by the fact that the machines employed
to carry it out vary in weight from considerably under half a hundredweight to
many tons.
As has been already mentioned, resistance welding resembles in several respects
the welding of the ordinary smith. But, though like it in some ways, it is very different
from it in others, and perhaps, before all, in that the heating and welding operations
are performed practically at the same time and almost instantaneously. As soon as
welding heat is reached, the welding is immediately effected, and in the lighter kinds
of work the rapidity with which the welding heat is attained is quite remarkable.
Although the process is not applicable to every sort and kind of welding, yet the
sphere of its utility is very wide, and the quality of the work effected by it unquestion-
ably good. It is necessary for its effective operation to have at command heavy flows of
current, but, on the other hand, the voltage necessary is very low. In some cases as
low an electromotive force as- half a volt is aU that is required. In actual practice,
from four to six volts is about the highest pressure worked with, though in some
special machines recently built in America higher voltages than those named are
employed. The temperature of the metal to be welded is raised simply by allowing
a very heavy current to flow through a restricted area, and to those who are unac-
quainted with the process, the rapidity with which welding heat is arrived at when
using properly designed and proportioned machines will appear extraordinary.
As can be well imagined, the difiSculties attending the use of direct current for this
system of welding are practically insuperable, except for the welding of exceedingly
small articles. It is, however, only the difficulty of using it which precludes its com-
mercial use in thid direction. It is not because resistance welds cannot be made with
direct current. For the purpose, direct current would be just as effective as alter-
nating, bub there is no comparison between the relative ease with which the two
kinds of current may be applied. With the former, the heavy current has to traverse
the whole of the machinery involved, whereas in an alternating system the heavy
welding current only flows in part of 'the apparatus where it can be accommodated
without any trouble. The supply voltage may be anything within reason. All that
is necessary is co to proportion the primary and secondary winding of the welding
machine that the desired secondary voltage is obtained. In the large majority of
cases the secondary winding only consists, as in the original Thomson machine, of one
turn, the two terminals of which are short-circuited by the object or objects which it is
desired to weld. In such a case, supposing a secondary pressure of one volt to be
required with a primary voltage of, say, 500, then the primary winding would be
ELECTRIC WELDING AND WELDING APPLIANCES
composed of 500 turns, and the conductor of the secondary irould need to have a
carrying capacity of 500 times that of the primary. As for some purposes many
thousands of amperes are required, it can readily be seen that the cross-sectional area
of the secondary conductor must, in some cases, be very large. Generally speaking, the
one turn of the secondary is built up of a large number of thin sheets or ribbons of
hard copper joined in parallel, the reason for this subdivision being that flexibility is
desired. The two sets of ends of these sheets of copper are
attached respectively to two heavy copper jaws or terminal
pieces, which have to be capable of motion towards and away
from one another, so that the object or objects to be welded
may be pressed together. The junction between the many
sheetB of the secondary winding and these terminal pieces or
jaws is effected as carefully as possible, so that there may be
perfect electrical connection, and that each strand of the coil
may carry its proportion of current. The jaws or terminal
pieces are made of many fcrms to suit different kinds of
work, and since they are liable to become very hot during
continuous welding operations, they are, as a rule, made very
massive, and are almost universally cooled by water circulated
through cavities formed in their interiors. The simplest
form of rcBistance welding machine is shown in Fig. 8, which
represents dii^ammatic^y the Thomson principle. It will be
realised that, if the articles or parts to be welded are introduced
between the two terminals of the secondary winding, the circuit
of the latter will be closed and current will flow if the primary winding be energised.
Stated briefly, the machine is completed (a) by means for bringing the two terminals
nearer to one another, so as Srst of all to close the electric circuit and afterwards,
when welding heat is attained, to apply pressure to the heated parts, so as to form the
weld, and (b) by means for energising and de-energising the primary winding. In,
many cases these two motions are interlocked 60 that they may work in unison and
Primary
Winding.
wmmM
Secondary
Winding-
Fia. 8.— Diagram of
Thomson Wei ding System.
FiQ. 9. — Diagram showing Principle ol Spot Welding.
«o that the current may be cut off when welding beat is reached, and just before the
final pressure comes on. The mechanism used for advancing and withdrawing the
jaws and terminal pieces or electrodes is of a varjdng character, depending on the
nature of the work to be dealt with, and on the taste and fancy of the designer. There
are machines which are operated by a hand lever ; others in which the lever is worked
by foot, while in some cases the motion is provided by a hand wheel and quick pitched
Ecrew, and in others by a hydraulic cylinder. There are machines which are power
RESISTANCE WELDING
17
driven, so that the top electrode is continuously being moved up and down, a weld
being made at each stroke, if there be material to be welded between the jaiws or
electrodes. Such machines may be automatic, in that the currently turned on and off
and the pressure applied and relieved without requiring to be touched by the atten-
dant, who has only to concentrate his attention on the articles to be welded.
c
o
\ y Cilinder being Welded.
( C \-Roll6r.
N-T-'
I
A
Swain 8&
Fig. 10. — Diagram showing Principle of Seam Welding.
Some machines may be made available for a large number of different welding
operations, but it is frequently necessary to have specially designed machines for
special classes of welds. In fact, for each of the three resistance welding methods to
which we have already made reference, i.e. (1) Butt welding, (2) spot welding,
C/amping
Jaws. ^
^Hg ENQiNccft" Swain Sc-
Fig. 11. — Diagram showing Butt Welding of Tyres.
(3) seam welding, many different types of machine have been evolved. To some of
them we shall refer in later chapters. In aU of them, however, the electric principle
is the same. Comparatively high voltage alternating current of smaU volume is trans-
formed in a static transformer, which actually forms an integral part of the welding
E.W. C
18 ELECTRIC WELDING AND WELDING APPUAXCES
machine, to large volume with very low voltage. The differraiees between the
varioofl machines consist, among other things, in (a) size, (6) the means of applying
the pressure and cutting the current on and off, and (c) in the forms of the
terminal pieces, jaws or electrodes of the secondary windings, and of the arms
carrying them. Just as in a hydrauUc riveting machine it is necessary- to have
a considerable depth of gap, so it is with certain types of electric welders. The
arms holding the electrodes are, in such cases, long. A diagrammatic example of
such a case is shown in Fig. 9. On the other hand, there are many things which can
be welded while held in the hand simply by being placed between two advancing
jaws. In other cases, such as in that of such things as the rims of bicycles, the two
ends to be welded have to be held tightly in clamps, which, when moved towards one
another, cause the edges to be welded to press against each other. A diagrammatic
sketch of such an arrangement is shown in Fig. 11. Then again, for seam welding the
electrodes may consist of wheels or rollers as shown diagrammaticaUy in Fig. 10.
Machines of this type are employed for the seam welding of cylindrical articles.
CHAPTER IV
ARC WELDING AT A STEEL BARREL WORKS
The work carried out by the Steel Barrel Company, of Uxbridge, affords an excellent
example of the employment of different welding processes for varying kinds of work,
and would appear to confirm the assumption thab, as far as can be Seen at present,
both arc and resistance welding, as well as the acetylene method, have come to stop*
For upwards of twenty years now the company has been using electric arc welding,
and it has more recently adopted resistance welding and the oxy-acetylene flame for
operations for which arc welding is less suitable. An account of what is being done at its
establishment at Phcenix Wharf, Uxbridge, should, therefore, prove of interest.
At the outset it may be explained that the output of the works consists not only
of the steel barrels which the name of the Arm would lead one to expect, but cylindrical
steel vessels of all descriptions from small drums to large tanks capable of- holding
3000 gallons or so, and of withstanding heavy internal or external pressures. The
products include such things as buoys, cylindrical casks and vessels of all sorts and
sizes, and even, we understand, small steam boilers at times. The material employed
is steel sheet or plate of varying thickness, and we believe we are right in saying that
every joint is welded, not a single rivet being used in anything which iA made.
As acetylene welding does not come within the scope of this Work we may
dismiss its employment at Uxbridge with a few words, though in so doing we must
not be understood to infer that the process is regarded by the firm as being of small
value, for that is far from being the case. Indeed, Mr. T. T. Heatou, the company's-
managing director, who has certainly had as much experience as, and probably more
than anyone else in the country in methods of welding other than those practised by
the smith, regards it as a most useful adjunct to his electric equipment, and ad being
exceedingly well adapted for certain classes of work — in fact, in its sphere, better than
any of the electric arc processes. In some cases the particular utility of the acetylene
flame is due to the fact that its
temperature is considerably lower than
that of the electric arc. Hence it can
be employed with thinner material
than is practicable, without burning the
meta], by any but a most experienced
operator with the carbon arc.
As far, however, as our own personal
observation went, on the occasions which
were courteously afforded us recently of
visiting the works, the special use to which the acetylene blowpipe, is put is in
building up work over comparatively wide areas, such as in the joints connecting
outwardly dished ends to cylinders of large diameter, and made with comparatively
thick plates. In work such as this it is the firm's custom to build up a layer of
material round the external joint in ouch a way that the step that is shown in the
left-hand view of Fig. 12 is entirely obliterated, the joint being made to have the
Joint
"^HC Enoinccr"
Swiuii
Fig. 12.
20
ELECTRIC WELDING AND WELDING APPLIANCES
appearance shown in the right-hand view. The width of the welded portion was, in
the cases which we have in mind, 2 in., or something over. For such operations as
this, Mr. Heaton has found the acetylene flame to produce better results than the
electric arc.
Passing on to steel barrel manufacture, it may be first explained that only the
carbon arc system is employed, and that it is carried on in exactly the same manner
as it was when revised by its inventors, Benardos and Olszewski, the " work " forming
the positive pole, and the carbon the negative pole of a direct current arc. The
requisite accessories are of the simplest description. There is, first of all, a source of
electrical energy with a voltage of 90 ; then there are : (a) a resistance of coiled
wire carried in a wooden frame attached to the wall ; (b) a flexible cable connecting the
resistance with (c), an electric holder of a very simple type, and (rf) a c&rbon electrode.
In pre-war times graphite electrodes were employed, but owing to the difficulty in
Hexible
Ca6/e.
•*TmC CNaiHUR**
Fig. 13.— Carbon Electrode Holder.
GwAiN Sa
obtaining them during the war period ordinary carbons are now used, and they
answer perfectly, though the resistance of the carbon is somewhat higher than that of
the graphite. The holder consists of a wooden handle with a hole through it from end
to end for the passage of the flexible conducting cable, and furnished with a heavy
brass cap or ferrule to which are attached, in addition to the cable, two strips or arms
of steel, 15 in. long or so. Riveted to the outer end of each of these arms is a stout
steel plate, an inch or so square and a quarter of an inch thick. Each plate has a
groove out in it, so that the two plates when pressed together may so clasp the electrode
that it is held firmly. Pressure is applied by means of a screwed bolt and butterfly
nut, the former passing through holes in the two clip arms. The apparatus, the
appearance of which is roughly shown in the accompanying sketch. Fig. 13, is com-
pleted by a large circular screen some 9 in. in dijimeter, and made of tinned sheet
steel, which is attached to the wooden handle, and is, of course, for protecting the
hand and arm of the operator from the effects of the rays emanating from the arc.
The only other accessory is a hand screen, some 18 in. square, furnished with a handle,
and having a rectangular opening in its centre measuring about 6 in. by 3 in., which
is covered by three glasses. That which is held facing the arc is ordinary blue
ARC WELDING AT A STEEL BARREL WORKS 21
glass, and its purpose is only to protect the glasses behind it from splashes of
metal. Of the other two glasses, one is deep ruby and the other deep blue. We
gathered that no particular precautions are taken to examine these glasses spectro-
soopically. They are simply bought, of the darkest shades possible, in the open
market. The handle is further protected by an auxiliary screen which envelops. and
protects the left hand of the operator. Each welding space is partitioned off from
those on either side of it, and from the rest of the shop by screens of sacking.
We may here say that no ill-effects have been experienced with the eyes, face,
hands, or arms of any of the operators, when the appliances provided have been
properly used and reasonable precautions taken. It will be realised^ however, that
there is some small disadvantage in the use of combined deep ruby and deep blue
glasses, in that it is quite impossible to see anything through them unless the arc has
been actually struck. For some little time now the company has been studying the
question with a view to obtaining glass which, while preventing the passage of harm-
ful rays, would allow the operator a better view of his work. So far, however, it has,
we gather, been unable to obtain glass — such, for example, as Crookes' glass — ^in pieces
large enough to suit the particular requirements. The ruby and blue glasses have
dene very well for over twenty years, and from our own experience We can say that,
as soon as the arc is struck it is perfectly easy to watch the welding operations minutely,
even when standing at some little distance away.
To the anexperienced onlooker the welding operation might seem to be quite
sifnple, but, as a matter of fact, it requires no inconsiderable amount of skill. Mr.
Heaton is of opinion that, taking the sum total of the factors going to make up a
successful carbon arc weld as one hundred, operating skill would be represented at
sixty. Yet it is skill which is not, by any means, insurmountably difficult to acquire.
Some of the operators who have been trained into highly successful workmen had
had no previous mechanical or scientific experience. We observed two men who were
doing excellent work whose original occupations had been, we were informed, that of
milkmen. A man of average intelligence can, we gather, be trained to carry out the
simpler operations within a period of some three months. <,
A description of the making of an ordinary steel barrel will give a good idea of the
general run of this department of the firm's activities. A sheet of steel of the required
dze and gauge is first of all passed several times through a pair of rolls, so shaped as to
give the metal the required curvature and form. The edges which are to be welded are
then accurately marked off and sheared in a machine which was specially designed for
this purpose. A hole, which is eventually to receive the bung-ring, is then punched.
The bent sheet is then clipped on to a substantial anvil arm which has the same curva-
ture as a completed barrel and hence, also, as the rolled sheet. A space of about one-
eighth of an inch is left between the two sheared edges, which are arranged to come
immediately over the centre of the anvil arm, which is connected to the positive
pole of the electric supply.
The welding of the seam is done in lengths of about 6 in. The procedure is as follows :
A shearing of steel sheet of the same composition as the sheet being welded, about
i in. wide, ^ in. thick, and some 6 in. long, is laid flat immediately over the lengtii of
seam which it has been decided to weld first. Usually it is at one end of the seam,
though the exact position does not appear to matter* The operator then, with the
screen in his left hand and the electrode holder in his right, brings th*5 point of the
carbon electrode into contact with the work, and immediately withdraws it.. The
result is, of course, the formation of fl,n arc, which, in the operations that wo watched,
was varied during the process from about 1^ in. to 2 in. in length. This arc is made to
22 ELECTRIC WELDING AND WELDING APPLIANCES
play on the piece of sheared metal just mentioned, being moved from end to end of it,
until, in a remarkably short spaoe of time, the whole is a white-hot mass. The operator
then causes the arc to play on the metal sheet on either side and at the ends of this
white-hot mass, taking it round and round the latter until the correct welding heat is
reached, which is judged by the appearance of the metal. The arc is then smartly
broken by withdrawing the electrode quickly, and the weld is consolidated by a few
blowd of a wide-faced flat hammer. This cycle of operations is repeated until the whole
length of the seam has been welded. The seam of a barrel to hold 100 gallons is
welded in from nine to ten minutes.
It might be asked why the weld does not extend to the anvil so that the partly
formed barrel would adhere to it. That it does not do so is due, of course, to the fact
that, having large mass, the metal of the anvil is not raised to anything near welding
heat. Moreover, the arc is never allowed to play actually on the anvil itself ; there is
always some metal in between.
The art in the welding process is in keeping the temperature just right, neither too
high nor too low. If too high the metal is burnt, if too low a bad weld will result.
The temperature is regulated by the current flowing in the arc and by the length of time
the latter is allowed to play on any particular spot. The current is controlled to some
extent by the resistance in the external circuit, but not entirely. The operator can,
however, increase or decrease it at will, over a fairly wide range, by decreasing or
increasing respectively the length of the arc. He judges by the appearance of the
heated metal whether the temperature is correct or not, and he acts accordingly.
It is noteworthy that no flux whatever is used. The company never has used any.
It maintains that, provided the operation is skilfully performed, there is, for mild steel,
no necessity to use a flux either to assist in the flow of the metal or to prevent oxida-
tion. It will be remembered that it is only the strap — ^if suoh a description may be
applied to the added piece of metal — ^which is actuaUy melted, and, as we saw it, it was
only just melted and not raised nearly to the burning point. The metal on either side
of it was not brought to nearly Such a high temperature, as was quite evident from the
colour. The result, howevOT, is that a perfect joint is produced, which is only very
slightly thicker than the sheet, the edges of which it unites and which is quite smooth.
The next process is the welding-in of the bung receiver, which is a ring of mild
steel, with its hole screwed to receive the bung and with a fairly wide shoulder which,
when the part with the smaller diameter is inserted in the punched hole, prevents
the ring from falling through. This shoulder also serves another purpose. There is no
added metal as in the longitudinal seam of the barrel, but a large proportion of the
shoulder itself is melted by the arc being made to play on the periphery of the ring.
At the same time the temperature of the metal sheet of the barrel is raised to such a
point that fusion takes place between it and the metal of the ring. Hammering is not
resorted to, and it can well be imagined that considerable skill is required correctly
to regulate the heat. In some cases the bung ring is only welded on the outside in the
manner just described, but in others it is welded inside as well. We observed no
tendency to distortion either in the welding-in of the bung rings or in the formation
of the longitudinal seams. Moreover, we were informed that no injury was done to the
screw of the bung ring, though it may be necessary to run a sizing tap through the hole
if the bung wiU not screw in with sufficient ease.
The filling in of the ends of the barrel is performed in the following manner : The
two end pieces are dished so as to form circular trays with rims about 1 in. deep.
They are of just the correct diameter to be driven into the open ends of the barrels,
which are left parallel to the axis for a sufficient length for that purpose. The appear-
ARC WELDING AT A STEEL BARREL WORKS
23
ance is then as shown diagrammatically in view " a " in Fig. 14, the thickness of the
metal being, of course, greatly exaggerated. Two steel rings R^ and R° are then placed
inside the dished end and outside the end of the barrel respectively. These rings are
made to fit fairly tightly, but no great care appears to be taken to make them fit
accurately all the way round. The appearance is then as shown in view '' 6 " in Fig.
14. The body of the barrel, which is stood on end, is then made the positive pole of an
electric circuit, and the operator then proceeds to strike an arc, with a carbon electrode
forming the negative pole of the circuit, on the upper surface X formed by the rings
R' and R°, the rim of the end piece, and the end of the barrel proper. In this maimer,
by taking the arc gradually right round the circle, all the four rings are welded together
as shown in view " c " in Fig. 14, and a stout projecting rim is formed which, from
the look of it, will stand a good lot of knocking about. Again no flux is used nor
is hammering required. The time taken to weld round the end of a barrel is about
1 J minutes per foot.
Finally, the ends are examined and any rough places removed by filing. As a
matter of fact, the work is left wonderfully flat and smooth, and only where the metal
has run over the edges of the inner or outer rings is any attention necessary as a rule.
End oFBarrei
"ar
**The Engimcer"
2ZZ2ZZ2ZZZZ^
EndoFBarrel
Side or
Bar re/-
V
C2Z
End oF Barrel
Side of
Barrel-
u^.
Fig. 14.— Welding-in the End of a Barrel.
Swain 8e.
All that now remains to be done is to test the completed barrel for tightness — ^which
is effect^ by immersing it in water and appljdng air pressure internally — fitting the
bung and painting. The average time taken to produce a complete barrel, including
rolling, welding the seam, fitting the bung ring, welding-in the ends, testing, painting,
etc., is about an hour.
The procedure with cylindrical vessels with paraUel sides is substantially the same,
but, of course, the plates are only rolled so as to form a cylinder, and are not bulged.
If stiffening rings are required they are threaded on and welded in place before the ends
are welded in. In some cases, too, when barrels are required to be speciaUy strong,
thick stiffening plates, bent into the form of rings and welded, are put over them where
their diameter is largest. The rings are bedded to the body of the barrel, and the edges
finally welded to the latter. The procedure is as follows : A welded ring of eheet
steel with an internal diameter exactly the same as the largest external diameter of the
barrel, or cask, which it is desired to strengthen, is slipped over the barrel, ad shown
diagrammatically in view " a " in Fig. 16. The ring is then connected to the positive
terminal of a direct current circuit and an arc is struck on one side, say, at " a:," by
means of a carbon electrode which forms the other pole of the circuit. A compara-
tively low current is employed, and the arc is not allowed to remain in one place, but
is quickly moved about over a considerable area until the metal in that area has
become red hot. The heated portion is then quickly hammered down with a largo
24
ELECTRIC WELDING AND WELDING APPLIANCES
flat hammer until it comes into close contact with the outside surface of the barrel, a
suitably shaped anvil arm being, of course, arranged inside the latter. Things are
then as shown diagrammatically in view '* 6 " in Fig. 15. This process is then repeated
on the other side, " y," of the ring, so that that side, too, is brought into contact with
the barrel. These processes are repeated all round the periphery of the barrel, so that
the bent ring is brought to the same shape as the barrel, as shown in the view " c " in
Fig. 16. Finally, the edges of the ring are welded aU round to the body of the barrel,
so that the ring adheres tightly to the latter and provides a most eflEective stiffening.
It may also be mentioned here that
when necessary the company cuts metal
by means of the electric arc.
The electric energy used in the
foregoing processes is generated on the
site. There are two vertical high-speed
steam engines, one by Belliss and
Morcom and the other by Browett-
lindley. They obtain their steam from
two hand-fired Lancashire boilers, and
each drives a ^00-kilowatt direct current
generator. The voltage is 90, and the
available current is, therefore, about
4500 amperes. When in full work
twenty welders are employed, and each
dynamo supplies current to ten welders.
The voltage across the welding arc varies, of course, with the resistance in circuit
and the length of the arc itself, and the variation is usuaUy within the Umits of 50
to 56 volts. There are no instruments by which the operator can tell what the
voltage is, or what current is passing. His experience tells him if the conditions are
as he wants them. If they are not, he can make the necessary correction by altering
the length of his arc. There are, however, instruments on the switchboard in the
engine-room by which the operations of each of the workmen can be checked. We
gather that for ordinary welding work the current employed is somewhere in the
neighbourhood of 300 amperes. For such a current carbons 15 mm. in diameter and
12 in. long are employed, and they last for some few hours.
As to the quality of the work done there can be no two opinions ; it is excellent,
and it has stood the test of many years' cervice. It is quite evident, therefore, that for
the particular articles dealt with at Uxbridge the carbon arc process is, in skilful hands,
and without the use of flux of any kind, perfectly successful and satisfactory.
We defer a description of the resistance welding system employed in these works
to a subsequent chapter.
"The Enoinccr"
Fig. 15. — Putting on Stiffening Ring.
Swain 8c
' CHAPTER V
THE PONTELEC METHODS AND MACHINES
i
The business of Pontelec Welding Patents, Limited, dates from early times as elec-
trical matters go. Mr. A. Jevons, who succeeded Woodhouse and Rawson United
(Midland Branch), Limited, and who was one of the pioneer contractors in electric
light and power, established himself in the Minories, Birmingham, in 1888. On the
introduction of electric welding he was appointed representative for the original
*' Thomson " patents, and he himself subsequently obtained patents for welding
the seams of tubes, chain welding plant, and automatic switches for welding machines.
His office was at Constitution Hill, Birmingham, and the present company, which
was formed to take over the rights of the Universal Electric Welding Company of
New York, fitted up a demonstration shop in the immediate neighbourhood. Even-
tually, owing to the keenness of continental competition, as well as to Mr. Jevons'
failing health, the company arranged to take over the latter's business, and removed
its plant to 46 Constitution Hill, at which place, for some years past, demonstrations
of its various special processes have been given, and also the manufacture of some
twenty-two different types of machines carried on.
We have recently had an opportunity of visiting the works and of observing a
number of machines in operation. Seeing that all the latter embody the Thomson
method of welding, single-phase alternating current is, of course, alone employed.
As the public supply available in the neighbourhood of the works is direct current
it was necessary to employ a means of converting it to alternating current. All elec-
trical engineers will realise the difficulty of dealing with 'a highly inductive load used
intermittently and often only at 0.6 power factor, thrown on and off, it may be, several
times per minute. However, the machine which is employed has, according to the
testimony of the company^ which has during the past few years purchased several of
them for use in various places, answered its purpose admirably. It was made by the
Phoenix Dynamo Manufacturing Company, Limited, of Bradford, which took up this
particular branch of the subject a number of years ago now, and, as a result, developed
a special design of inverted rotary converter.
The actual machine used at the Pontelec Works is of 50 kilovolt-ampere capacity.
It had, so we gathered, been running for over 8 years, and had been in almost con-
stant use during that period, frequently being csJled upon to work up to as much as
70 kilovolt-amperes, and -was still in good working order. The company, in fact,
was quite enthusiastic concerning its behavioui*, and we certainly saw it undergo some
fairly severe treatment.
It would be impossible for us to refer separately to all the many types and designs
of machines which this firm manufactures,' and we therefore propose to deal with only
a selection. The machine illustrated in Fig. 16 is typical of the firm's standard type,
a series of which is built in sizes varying from 6 to 100 kilowatts in capacity. In the
particular instance shown the working is effected, both as regards the electric and
mechanical arrangements involved, by means of the hand. In other forms, however,
the current can be switched on and off by means of a treadle. The whole apparatus
26 ELECTRIC WELDING AND WELDING APPUANCES
is wonderfully simple. The electric portion, which, with the exception of the switch
A and ammeter B at the top, is not visible in the engraving because it is hidden by-
parts in front of it, consists of a static transformer, the primary windii^ of which
comprises a number of turns, while the secondary winding is of one turn only. The
latter m made up of numerous strandB of thin
sheet copper, which are not only quite flexible,
but h^ve a negligible ohmic resistance. The
two terminals of this winding are respectively
connected to the two jaw carriers C and D,
whi-jh are mounted in slides formed on the
front of the machine. These jaw carriers, which
are, of course, electrically insulated from one
another, are capable of vertical motion upwards
and downwards in their slides. The upper jaw
carrier C is moved up and down by the manipu-
lation of the hand lever E, which operates
through the toggle F. The range of movement
is, therefore, always the some. In order that
articles of varying thickness may be received
within the jaws the lower jaw carrier D may be
moved vertically up and down by means of the
hand wheel H. The jaw carriers are formed of
heavy masses of copper, and they are cored out
so as to permit of water circulation. JawB of
V, or any other desired shape, can be fitted to
their faces.
In operation the article to be welded is
inserted between the jaws, the height of the
lower jaw being adjusted so that a very small
movement of the hand lever will cause the
work to be gripped. The circuit of the primarj'
coil is then completed by pulling the switch
handle rod A^, and current immediately begins
to flow in the secondary winding, since its
circuit is completed by the article between its
terminals. The flow of current is heavy, being
only limited' by the resistance offered by the
surfaces in contact, and by the article beiug
welded. The result is that the latter is verj-
quickly raised to welding heat, while the jaws,
because of their mass, and of the fact that they
have water circulating inside their carriers,
Flo. 16.— Pontelec EesisUnce Welder. remain comparatively cool, even when large
numbers of articles are welded consecutively.
As soon it,s weldiiig heat is reached — and the time it takes to do bo varies, of course,
with the nature of the article being dealt with, though it is never very long and is
frequently only a few eecondb — the current is cut off by opening the switch, and at
the same time additional pressure is put on the work by the hand lever and toggle,
and the weld is consolidated. We may say that it is impossible to pot excessive
pressure on the work with the toggle mechanism, since the pressure which can be
V.
THE PONTELEC METHODS AND MACHINES 27
exerted is controlled by the spring G. We have watched the machines of thifi type
doing a large variety of work, and dealing with articles ranging fr)m thin sheets
and fairly fine wire up to plates each three-eighths of an inch or so in thickness.
In some cases the pieces of material to be joined were simply laid one on the other
without any preparation. No special care, for instance, was taken to remove rust.
The company has developed and patented several processes for use in connection
with machines of this tjrpe. One of them, which is Imown as bridge welding — whence
the name of the firm " Pont-Elec " (trie) — consists of laying small pieces of metal
either over the joint of a tube or between two separate parts of an article, and placing
the whole between a pair of electrodes. When the current is allowed to flow and
welding temperature reached, pressure is applied, the metal is forced together, and
providing the superimposed pieces are close enough together a continuous joint
results. In a second process, which is termed multiple point welding, a number of
dents, or projections, is formed on either one, or both, parts to be united. In this
case contact only takes place at those points, so that when the current passes heating
is only set up in their neighbourhood, and when pressure is applied and intimate con-
tact effected the metal in those parts alone is welded. In some cases as many
as 20, or more, of these small welds can be made in an article at one operation, and
the tenacity with which the two portions of the welded article adhere to one another
can be imagined. For certain purposes machines working on this system can be
made automatic. The process is, of course, particularly suitable for thin metal work,
and the electrodeiS, or jaws, may have large flat surfaces. The company draws
attention to the fact that in this case it is the work or material being dealt with that
has the points on it, and not the electrodes, so that not only are more uniform results
obtained than with ordinary spot welding, but the electrodes, being removed from
the point of maximum temperature, are little affected, whereas with single-pointed
electrodes the copper points which, by reason of the high temperatures and the
hammer action to which they are subjected during the welding operation, are apt to
become flattened, which necessitates their being frequently attended to and reshaped.
A third process is particularly intended for use in connection with heavier work
such as the welding together of plates of half an inch or more in thickness. In such
operations it is an exceedingly difiScult matter to maintain the points of the electrodes
in good condition, even though the electrodes themselves are as efficiently water-cooled
as it is possible to make them. There is, moreover, another trouble in that, owing to
the plastic character of the metal being welded when heated, indentations on both
faces of the plate may be caused by the heavy pressures which are necessary to ensure
good welds with thick plates. Disc welding, as it is termed, has been devised to over-
come these troubles. It consists in placing small discs of the same metal as that which
is being operated on, on one or both sides of, and in some cases between, the parts
being welded, the first two discs being arranged at the points of contact between the
electrodes and the work. On the passage of the current, the parts heated are in this
way restricted to the area of the discs or something a little greater. Welding heat
is by this means obtained very quickly, and when pressure is applied the discs are
forced into the work. By suitably arranging the diameter and thickness of the discs
a flush surface results. If desired, too, bosses may be put on, and such bosses may be
shaped like rivet headd so as to give the finished article the appearance of having been
riveted. The company is careful to explain, however, that the strength would be
greater than that possessed by riveted work since the area of the weld is always some-
what greater than that of the superimposed disc. A particular advantage claimed
for this method is that greatly varying thicknesses of metal can be welded together
28 ELECTRIC WEIJ)IN'G AND WELDING APPLIANCES
without any chance of burning the thinner sheet. Thus by it, it is perfectly feasible
to weld a thin sheet of, Bay, 26 or 30 gauge on to a plate 1 in. or 1^ in. in thickness.
Still another process which can be practised with this machine is that known as
ridge welding. In it ridges are formed during rolling on the surfaces of the metal, so
that when the two articles to be welded are brought together the area in contact is
much reduced as compared with what it would be were the Rurfaces plain, and welding
only takes place along the ridges. This process, it is pointed out, is especially useful
in constructional work, but has not received in this country the attention which has
been accorded to it both on the Continent and in America,
We understand that a Ucence is required to use the special processes of this com-
Fio. 17.— Machine for Brazing Collars on Tabea.
pany, even though they are carried out on machines of another make, since the pro-
cesses themselves are subjects of patents.
Passing on now to some of the other machines made by this firm, attention may
be directed to Fig, 17, which shows a machine recently designed for brazing steel
collars on to tubes. In this case the electrodes have horizontal instead of vertical
motions, the pipe being dealt with being held vertically. The pipes seen in the en-
graving are for the water circulation, and give the machine the appearance of being
rather complicated, which, as a fact, it is not.
It will be observed the welding circuit is divided and forms three pairs of jaws, or
tools as the makers call them, the upper and lower pairs fitting the tube, whilst the
middle pair makes contact on opposite sides of the coUar to be brazed on. In opera-
tion, the handle an the right-hand side is pressed back and all three tools on that aide
are carried to the righti the left-hand tools being fixed. The collar is first placed in the
THE PONTELEC METHODS AND MACHINES 29
middle tool, resting upon. Bupports provided on the Inside of the tools. A ring of
br&zing wire is then placed on the collar and the tube passed through both from the top,
an adjustable support at the bottom — not seen in the engraving—taking the weight
of the tube and at the same time fixing the position of the collar in relation to the ends
of tube. The handle being then pulled forward, all three pairs of tools are brought
into contact with their respective parts, the secondary circuits being so arranged
that one is completed through the tube, which becomes heated midway between the
upper and lower contacts, whilst the other circuit is completed through the collar,
which becomes heated at the same time, there being only one primary circuit con-
trolled by a foot-switch so that the operator has both hands at liberty. A little borax
is applied and the current kept on until the brass wire flows into the joint between the
tube and the collar. Owing to the heat being internally generated, the outside of the
collar remains clean and nothing is needed, so we understand, but a rub over with a
wire brush, the whole operation only occupying about one minute. The tubes are about
one and five-sixteenths inches external diameter and one-quarter of an inch thick,
the collars being about one and one-quarter inches long, and three-eighths of an inch
Fig. 18. — Speclacle-frame Soldering Macliiae.
thick. The regulator provides six variations of power, with a maximum of 10 kilovolt
amperes.
Fig. 18 is interesting as shewing what is thought to be the smallest resistance
heating plant ever made commercially. It is not, strictly speaking, perhaps, a welding
machine any more than is the machine just described, but they both approach, we
think, sufficiently nearly thereto to warrant mention of them being made in this
Work. The whole apparatus is contained in an oak case which measures 10 in. each
way, and it weighs only about 28 lb. It was designed and built for the Army Spectacle
Department, and is used, so we are informed, for the hard soldering of spectacle frames.
The machine on the left is a 4 horse-power motor rewound, and slip rings added.
The transformer is enclosed in an oak case, which has a regulator attached to its side.
The small switch shown in between the two is intended to be foot-operated, and is
placed on the floor, the converter being arranged in any convenient position. The
small machine shown in front of the oak case consists of two end frames supporting
a pair of parallel bars carrying a pair of copper blocks, both insulated and connected
respectively to the two 'ends of the secondary winding, but capable of being moved
on the bars and fixed in position by a small thumbscrew. Each copper block carries
30 ELECTRIC WELDING AND WELDING APPLIANCES
a tool formed to hold the different parts, which are pressed together by a light apri ng.
On the foot>Bnit«h being closed the points of contact become heated, and hard solder,
in the form of a fine wire, is touched upon the heated parts, inth the result that it is
melted and, flowing in, forms a clean and neat joint. Several hundreds of spectacle
frames are, we are informed, completed by one operator per hour, whilst the heating
is eo local that ndjoining parts are not softened, and the articles are easily handled.
This machine has a maximum capacity of about 2 kilovolt-amperes. It is use<l on
both Kteel and gold-SUed fittings of spectacle frames.
Fig. 19.— Typical Pontelec Spot Welder. Fio. 20.— Spot Welder for Bench Work.
Spot welding machines of various types are made by the company. A typical
example of one of them is shown in Fig, 19. It is of a light type, and is operated by
pedal. It is intended speciaUy for welding hollow-ware previous to enamelling, and
is mad© in sizes ranging from 5 to 20 kilowatts in capacity. As will be observed, the
lower electrode or anvil is capable of adjustment vertically by moving it in its slide,
where it can be clamped in any desired position by the nuts and bolts which may be
seen in the engraving. The upper electrode can also be adjusted by the movement
of a nut up and down the vertical screwed spindle seen at the rear of "the pivoted arm.
The distance apart of the two electrode points, and hence the amount of pressure
applied during welding, can in this manner he arranged.
THE PONTELEC METHODS AND MACHINES 31
A much lighter type of spot welding machine for bench use is shown in Fig. 20,
It also is pedal worked, and it will be observed that the lower portion of the link con-
necting the pedal with the upper electrode is slotted, so that the latter can be raised
to admit larger or smaller work. Then, too, the amount of travel of the pedal, and
hence of the electrodes, can be regulated to suit the altered circumstances by means
of the two sets of screws seen at the bottom of the engraving. The spring connecting
the frame with the pedal operating link raises the latter, and hence the upper electrode
when presBure is t>aken ofi the pedal. It will be observed that there are two series of
terminals on the box at the side of
the framo. They are for employing
different tappings on the primary of
the transformer inside the machine,
so as to obtain different voltages in
the secondary to suit differing classes
of work. This, we may mention, is
an attribute possessed by the other
machines made by the company.
While on the subject of spot
welding machines, we may say that
on the occasion of our visit to the
Pontelec Company's works we were
shown the drawings of a very large
machine of that type — probably, it
-was thought, the largest which had
been undertaken in this country —
which was then under constraction
for an enterprising British firm. It
was to have copper arms 7 in. in
diameter, projecting 5 ft. clear from
the body of the machine, and its
weight, when completed, was to be
something over 5 tons. An interesting
insight into the range of machines
built by the firm may be obtained ^lo. 21.— Pontelec Butt Welder.
when comparison is made between
that weight and that of the spectacle-frame machine weighing 28 lb.
Fig. 21 shows one of a series of butt weldii^ machines, which are made
in sizes varying from 6 to 60 kilowatts capacity. The actual machine illustrated
had been specially designed for welding motor-cycle rims, which it does, we gather,
at the rate of 150 per hour, with a consumption of 12 kilovolt-amperes of energy. In
operation the two ends of the rim which are to be welded are gripped between
two specially formed jaws, which can be moved backwards and forwards
horizontally, so that pressure can he applied to the weld by means of a hand lever
and toggle mechanism, observable on the right of the picture. The electrodes have,
of course, water circulation. We have seen this machine in operation doing excellent
work. It is fitted with an oil break automatic out-ofi switch.
A machine of quite a different type, which nevertheless shares many features in
common with those already referred to, is shown in Fig. 22. It is a machine for welding
the seams of oyUnders, and its operation will be reaiUly understood. The cyfinder is
fixed in a frame which can be traversed backwards and forwardn by means of the
32 ELECTRIC WELDING AND WELDING APPUANCES
hand lever. The seam restB on a horizontal anvil which forme one of the electrodes,
and has its ends carried by uprightg which form part of the cylinder-holding
frame. The upper electrode is formed by a copper roller which is revolved by
power by means of a chain which in sufficiently slack to permit of the small
amount of movement necessary to bring the wheel into contact with the work. Both
anvil and wheel are water cooled.
When the cylinder is in position, the
bed and frame carrying it are moved
by the hand lever, so that one end
of the Beam may come directly under
the roller. The' latter is then depressed
until it just touches the work. The
pedal bwitch is then operated so that
current flows, while simultaneously
the pressure between the roller and
cylinder is increased, with the result
that the latter is gripped between
the anvil and the roller, and, by
reason of the rotation of the latter,
ia caused with its bed and frame to
move horizontally. The result is that
the wheel follows along and welds the
seam as the cylinder is gradually
traversed from one side to the other
of the machine. As in the machine
shown in Fig, 16, there is a spring
which prevents excessive pressure
beii^ put on the work. In giving
the foregoing descriptions of eelec-
tions of the machines made by this
firm, it is not pretended that all the
different types of machine which it
makes have been mentioned ; but a
fairly rejM^sciitative reference has
been made. The company, it may be
Fio. 32.— Typical Potitelec Seam Welder. mentioned, does not issue any
catalogue. It has found such a course
impossible because there is such a great variation in the voltages, periodicities and
systems of distribution, that hardly any two cases are ahke in every respect. In
some instances, for example, only polyphase current may be available, and it is not by
any means always permissible to put a welding load on one phase only. Then, again,
continuous current only may be available. It prefers, therefore, to treat each separate
case on its own merits, and is prepared, when supplied with full information, to give
its considered view of the matter ; and it lays stress on the fact that it makes a point
of never booking an order unless it is sure that a commercially satisfactory result
can be obtained.
CIL\PTER VI
THE QUASI-ARC PROCESS
As an example of coated metal electrode processes we have chosen that which is
known as the Quasi-arc process, and we discuss it in the following chapter : —
The Quasi-arc — or the " Quazarc," to lise the trade mark name that has been
adopted — process of electric welding is the invention of Mr. Arthur Percy Strohmenger,
of the Quasi-Arc Company, Limited, of 3 Laurence Pountney Hill, E.G. 4, who holds
several patents in connection with it. It is a fusion process, and the electrodes used
are coated in a special manner, both they and the method of their application having
been patented. The electrodes can only be obtained direct from the company, and
with each parcel is granted to the purchaser a direct licence for the use of the process
in conjunction with the electrodes supplied in that parcel, and for such use no royalty
is charged. The firm has extensive works in the East of London, and at them we have
had an opportunity of observing, not only the manufacture of the electrodes on a large
scale, but the actual process of welding in operation. Mr. Strohmenger, who, we be-
lieve, was bom in South Africa, has had, at any rate, a wide experience with the
asbestos deposits of that country. Our readers will remember much of the asbestos
found there is of a blue colour, and is largely composed of a ferrous silicate. Its
chemical composition is such that Mr. Strohmenger was led to the belief that it would
answer perfectly as a flux in electric welding. His first idea was to coat a metal rod
with the asbestos and to lay it along the joint or seam which it was intended to weld.
An arc was then struck by means of a carbon or other electrode, and both the coating
and metal rod were gradually melted, together with the edges to be welded, so that a
welded joint protected by a covering of flux or slag was obtained. We believe that
the character of the weld was all that could be desired, but the method was clumsy and
did not, moreover, permit of overhead working. So Mr. Strohmenger decided to use
the coated rod itself as the electrode, and he has since made certain improvements
in the manufacture of the electrodes themselves. Perhaps the most important of these
improvements is the introduction between th^ coating and the rod of a fine aluminium
wire which represents in bulk about two per cent, of that of the electrode metal itself.
It is claimed that the effect of adding the aluminium is that a strong reducing action
is brought about, the metal having a strong affinity for oxygen at welding temperature.
The asbestos itself acts as a reducing agent and forms a slag which covers the weld
and prevents oxidation. The alumina passes away with the slag and the coating
formed on the weld is easily chipped off by hammering, and removed with a stiff brush
when the metal has cooled. The temperature at which the coating melts can be con-
trolled to a certain extent by the addition of such compounds as aluminium silicate
or sodium silicate. We may say here that the coating is applied in the form of yarn,
and is so regularly put on that the surface of the rods is quite smooth to the touch.
Under the Quasi-arc System either single phase alternating or direct current can
be employed. When we saw it in operation direct current was used. The supply
voltage was 1 10, and beyond the special holder for the electrode the only other acces-
sories were a resistance and an ammeter, and, of course, the protecting screen. The
E.W. D
34 ELECTRIC WELDING AND WELDING APPLIANCES
negative pole of the current supply ie connected to the work or to the metal plate or
bench on which the work to be welded rests, though in the latter case it is, of course,
neoeesary to make certain that there is good electrical connection between the work
and the plate. The positive terminal of the electric supply is connected to one ter-
minal of the resistance, the other terminal being connected by means of a flexible
cable with the electrode holder. One end of the electrode is left bare of coating and
it is, of course, that end which is imerted in the holder. In working, the electrode
IB first of all held in a nearly vertical position — supposing the work to be horizontal —
and when the tip of the electrode ia brought into contact with the work an arc is
formed. The electrode, still kept in contact with the work, is then dropped to an angle,
and the are is destroyed owing to the covering passing into an igneous state, and,
as a secondary conductor, maintaining electrical connection between the work and
the metallic core of the electrode. The action once started, the electrode melts at
an uniform rate, so long ae it remains in contact with the work, and leaves a seam of
metal, which, if the operation has been properly performed, is perfectly fused into
the work. The covering material of the
electrode acts as a slag and spreads over
the surface of the weld as it is formed,
and it is claimed that the fused metal is
thereby protected from all risk of oxida-
tion. It is recommended that the operator
should commence at the furthest point of
the joint away from himself, and bring
the electrode towards himself with a
V ^ slightly to-and-fro movement so as to
^-Enlarged diaarsm of Weld siH!yi,«gm(,t,o'ia,<'e- Spread thc heat and the deposited metal
THt e™.,.." «""«■ ^^_ ^ equally to both sides of the jomt. This
Fio. S3. zigzag movement, and the appearance
of the weld formed by means of it, are
shown in the accompanying engraving. Fig. 23. The length of the arc varies, we
gather, between ^ in. and J in., depending on the size of the electrode used.
It is necessary, of course, that care should be taken to feed down the electrode to
the work at the same rat© as the former melts away, and the operator is warned
not to draw the electrode away from the work so as to form a continuous arc, as by
doing so the quality of the metal laid on will be impaired, and the work, if thin, may
be burnt. The aim, it is explained, should be to keep the electrode just in the molten
elag, and this may be done by the " feel " of the covering just rubbing on the work.
Care must also be taken to see that the " work " is fused or melted where metal
is being depouted. It is quite possible, as we ourselves observed, to distinguish
between molten slag and molten metal when using the Special screens employed by
the company, the metal being dull red in colour, and the slag very bright rod.
In discussing the sphere of its applications the company states that the Quasi-aro
process can be used for a variety of purposes, such as constructional eteel work, in-
cluding shipbuilding, in the manufacture of pressure tanks, air receivers in boiler
work, including the reinforcing of worn plates and general repairs, and in the making
up of crank-shaft journals, worn key beds, repairs to hydraulic rams. It claims, too,
that the ease with which seams of any length and thickness can be welded renders
it most useful in industries in which hitherto riveting and caulking has been solely
employed — see Fig. 24 — and that on plate work it shows a high percentage of saving
in cost as compared with oxy-acetylene welding, being more than twice as rapid.
"The Encimeer" 8<vmm Sc
THE QUASI-ARC PROCESS 36
and the resulting joint much stronger, while there are no difficulties owing to distor-
tion of the work. On this point, which is due to the heat being highly localised, great
stress is laid. With regard to the foregoing it may be said that practically identical
claims are made by other arc welding specialists, who would hence dispute that they
are peculiar to the Quasi-arc process. They may therefore be taken as being indica-
tive of what can be done with metallic arc welding in general.
The Quasi-arc electrodes ad supplied are in lengths of 18 in., and they are of various
diameters, according to the size and nature of the work for which they are required.
For the general welding of mild steel or iron, constructional work, tanks, wheel tyres,
filling steel castings, etc., mild steel
electrodes are supplied and in the ^vifeid
following sizes : S.W.G. Nos. 14, 12,
10, 8, 6, and 4. For reinforcing worn
parts of machinery, building up the
teeth of gear wheels, reinforcing tram- Fig. 24.— Welded Riveted Joint,
way rail treads, etc., there are carbon
steel electrodes. As being suitable for reinforcing or building up manganese steel
crusher jaws, dredger bucket lips, tramway points and crossings, manganese steel
electrodes are recommended. They are made ^^ in. in diameter. Finally there
are special electrodes for boiler plate reinforcement and any overhead or vertical
work.
With regard to the sizes of electrode required for different sizes of work in sheet
and plate welding the company publishes a table which we reproduce on page 37.
It will be noticed that in thick work no attempt is made to do the whole depth of
the weld at one operation. The process is, in fact, essentially a building-up process.
Two, three, four or even more " runs " may be required, a proportion of the depth
being filled in at each " run." For the bottom portion a comparatively small electrode
is used, so that its point may be taken down to near the bottom of the seam. It
need hardly be said that the slag from a preceding '^ run " must be chipped or brushed
away before a further " run " is commenced, and that care must be taken to fuse the
surface of the preceding layer of metal as well as the sides of the joint whilst depositing
new metal.
As regards special precautions to be taken whilst welding by this process, the
company recommends that the electrode holder should be gripped firmly, but the
arm left free ; a light touch and a lateral movement from the wrist give the best
results. Sufficient current should be used to admit of the metal, which is being
d^eposited, running freely, with no tendency to pile up. If too much current be used
the metal will run fiercely and be uncontrollable. The point of the electrode should
be kept weU down to the work, just in contact, in fact, with the molten slag, and at
such an angle as will keep the molten metal and the slag flowing in front of the electrode,
that is to say, away from the operator, who, it will be remembered, gradually draws
the electrode towards himself. Care should be taken not to allow the slag to get
behind the electrode, that id between it and the operator. We have already explained
that slag can readily be distinguished from metal by reason of the (Ufference in
colours.
The following table gives the limits of current admissible with various sizes of
Quasi-arc electrodes : —
36
ELECTRIC WELDING AND WELDING APPLIANCES
Current limits.
Size of electrode.
(amperes).
No. 14S.W.G. .
.. 15 to 40
» 12
.. 35 „ 90
„ 10
.. 75 „ 110
„ 8
.. 90 „ 140
» 6
.. 110 „ 175
„ 4
.. 140 ., 200
iin.
.. 150 „ 220
fin.
.. 250 „ 300
The following remarks which the company makes regarding special applications
of the process are of interest : For reinforcing worn or weak work and for the repair
of faulty castings, the size of the electrode wiU depend upon the amount of work to be
deposited, but, in the case of work liable to distortion, overheating by the use of
unduly large electrodes must be avoided. In other words, it is a mistake to attempt
to lay on too much metal at one operation. For reinforcing work, such as the repair
of a worn crank shaft, the new metal should be deposited in strips parallel to the shaft,
and each strip should be cleaned of slag, etc., before the next is deposited at the side
of it. Then again, before commencing to fill up blow-holes the work should be pre-
pared by opening it out sufficiently with a chisel, or by fusing away the overhanging
portions with an electrode — using a higher current than for welding — so as to enable
the bottom of the hole to be reached by the electrode when welding.
Overhead welding, for which, as mentioned above, special electrodes are pro-
vided, takes longer than a seam of similar length on the flat. Good, sound homogeneous
metal can, it is said, be fused into the joints by holding the electrodes nearly vertical
and moving slightly from side to side, keeping the point of the electrode close to the
work. The weld should then be chipped over until an even surface is left, and then
other " runs " put on until the required thickness is obtained. For vertical welding,
the ordinary mild steel electrode may be used up to No. 8 size, the best angle to hold
the electrode being just below the horizontal. Most operators, the firm states, obtain
the best results by commencing at the bottom of the joint and working upwards,
although the process should be reversed when welding in an angle fillet. When suffi-
cient metal has been put on, if the electrode is worked downwards from the top with
a sHghtly higher current, it will have a smoothing effect on the metal previously de-
posited. We may say that, as far as we are aware, hammering is very rarely, if ever,
used with this process. The seams which we saw, whether they were horizontal,
vertical, or overhead, had a rippled surface — caused, doubtless, by the zigzag move-
ment given to the electrode — which stood up shghtly above the surface of the work.
When the slag was chipped off ?ifter welding, the deposited metal was perfectly bright
and not in the least discoloured.
For welding cast iron it is best, the company states, to use a small diameter elec-
trode and a low current, so as to retain as large a percentage of the silicon as possible
in the neighbourhood of the weld and thus keep the metal soft. Good grey iron,
high in siUcon and low in phosphorus, welds the best. In welding heavy cast iron —
say, above | in. thickness — ^it is best to vee out the crack, weld in at the bottom
with a small electrode, and then build up with successive layers of metal. In welding
light castings of box section, it is advisable to heat the casting to a black heat, to
relieve local strains, and then to weld over the crack without vee-ing. This operation
will result in the welding going quite half-way through. If the underside of the crack
is accessible it is advisable to repeat the operation from that side.
Though not strictly coming within the scope of this Work we may briefly
THE QUASI-ARC PROCESS
37
refer, here, to cutting metals by means of the Quasi-arc process. For this purpose
the company recommends the use of a mild steel electrode of No. 8 gauge. Just before
commencing operations the electrode is dipped in water, then, the resistance having
been set to give a current of about 200 amperes, the point of the electrode is applied
to the plate to be cut. The molten metal is allowed to drop away, and the cut formed
is followed up by feeding in the electrode and moving the point of the latter quickly
Sizes op Quasi-arc Electrodbs and Current Required for Sheet and Plate Welding
Thickness of
work.
j>
j»
>>
Preparatiou of joint.
Close joint
i>
>>
j>
open
i in. plate
I and I in.
16 s.w.g.
14
12
10
/ij^ in. plate I j'^^ in. open
I in. plate I Veed half-way through and -^^ in
yV hi- and f in. ^ Veed right through to 70 deg. and x^tf in. open
Two runs are necessary —
First run
Second
Veed right through to 60 deg. and J in. open . .
Two runs are necessary —
First run
Second run
Veed right through to 60 deg. and J in. open . .
Three runs are necessary —
First run
Second run
Third run
Over I in. Prepare thus : —
/fi^l*-
Up to f in. carry the 60 deg. angle, then parallel
upwards through the thickness of the plate.
After welding as for | in. fill up with
For heavy plates, say, l^in. thick, it may be
sometimes advisable to vee half-way
through from both sides
Size of
electrode.
No. 14
12
12
10
10
8
>>
>>
))
99
10
8
10
6
10
8
6
>>
Current
in amp.
20 to
30 „
40
50
75
93
ii
99
>>
>>
16
95
lo
100
75
95
100
»>
91
99
91
25
35
45
65
95
110
85
110
85-
120
85.
110
120
150 „ 175
up and down through the thickness of the plate. During the process the electrode
is again dipped once or twice in water. The point of the electrode should always be
kept as close as possible to the metal to be cut, but not so close as to get a dead short
circuit. If that occurs the electrode will stick and get red hot.
As regards the ease with which the operator can learn to employ this process we
are enabled to give the following testimony of an independent witness who is entirely
unconnected with the company. He says : " Electric welding by this method is not
difficult to learn, and with good instruction, skill in it can be acquired, and fairly good
welds produced, after one or two weeks of practice, according to the abilitv of the
38 ELECTRIC WELDING AND WELDING APPLIANCES
learner. ,The work is Buitable for female and other unskilled labour. The welder
may either stand or sit to the work. If the weld is of long duration it is advisable
to provide seats, particularly for female operators, so as to make them as comfortable
as possible. Neither the quality of the welds nor the speed at which they are effected
suffers from this attention." Here again, we would say, that advocates of other
covered electrodes make practically identical claims for their products.
CHAPTER VII.
RESISTANCE WELDERS OF THE BRITISH INSULATED AND
HELSBY COMPANY
To say that the British Insulated and Helsby Cables, Limited, of Prescot, Lanes.,
makes an infinity of machines for electric welding on the redstance system would,
of course, be an exaggeration, yet one is almost tempted to make such an assertion
when contemplating the multiplicity of designs which it has evolved for effecting
numerous operations.
We shall not attempt, therefore, even to give a full list of, much less to describe
all the machines which it is prepared to supply, though such a description would be
full of interest, but shaU content ourselves with referring to what may be termed a
fairly representative selection. We may premise what we have to say by explaining
that the electric arrangements involved in all the machines are f undamentaUy the same
as those employed in all systems of resistance welding. That is to say, each machine
embodies a transformer wound so as to perform the particular work desired under the
conditions of voltage and periodicity of the supply current available. The secondary
coil of the transformer consists of a single convolution, having a large cross section of
copper, which terminates externally in two electrodes, which are of various forms.
The pieces to be welded are brought between these electrodes, thus completing the
electric circuit of the secondary coil, so that when the primary circuit is closed a heavy
current flows in the former. As the resistance to the flow of that current is practicaUy
all centred in the surfaces in contact — since the ohmic resistance of the secondary
winding is compai'atively negligible — great heat is developed between the electrodes,
and the material between them is quickly brought up to welding temperature. There
is in each machine provision for regulating the pressure at the points of contact, and
also for cutting off the current at the right moment. The latter operation is, in some
cased, performed automatically, though in others it is effected by a separate motion.
Generally speaking, too, there are means of altering the current in the secondary by
means of tappings on the primary winding. Such in brief outline are the general
principles underlying the working of the machines, which we can now proceed to refer
to in greater detail.
In the first instance attention may be drawn to butt welding machined, of which
the company makes various types to suit different purposes, the princip€il being :
(1) Welders for wire with automatic upsetting gear for uniform section iron, steel
or non-ferrous metals ; (2) welders for manufacturing purposes with hand or automatic
upsetting gear for irregular section, iron, steel, or non-ferrous metals ; and (3) chain
welders.
" Wire welders " is the term which the firm itself applies to the machines in cate-
gory No. 1, and some of the machines made are capable of dealing with wire with as
small a diameter as 0.024 in. Other and larger machines of the same type are, how-
ever, able to weld material up to 1 square inch in cross section. Such machines are all
fitted with automatic upsetting and current control gear. With them the parts to be
welded are clamped between the jaws of the welder and the ends held together under
40 ELECTRIC WELDING AXD WELDIXG APPUAXCES
spring preBsure. When the current ia switched on beating occurs at the junction to
the two pieces, and when the heat is high enough to penuit of it, the ends are forced
together into still more intimate contact by the action of the spring and the current
is automatically switched off. Wires joined in this manner are subsequently redrawn
BO as to do away with the thickened portion where the upsetting has taken place.
The machines in the second cat^ory are used for such manufacturing purposes,
amongst a host of others, as welding pipes, refrigerator coils, milk-can rings, peram-
bulator rims, printers' chases, fittings to casement frames, carriage and coach work
parts, trellis work, coupling links, brake rigging, travelling-bag frames, low grade steel
shanks on to high grade steel tools, drills, taps, etc., lubricators, valves. t\-res, etc.,
FlO. 25.— B.I.W. Butt Welder, No. B7.
and for the building up of drop-forged parts into complete forgings. They work very
much as do the co-called wire welders, saving that in the majority of cases the switch
and upsetting gear are hand controlled instead of being automatic.
The chain wekiers really form a class by themselves, though the general principles
involved are very much the same as those of the other machines, as we shall show when
we come to describe them.
Two examples of the firm's butt welding machines are shown in Figs. 25 and 27.
The first-named is what is known as welder No. 57, and it has been designed to deal
with welds up to 5 square inches in cross section, and to be suitable for welding bars,
tyres, etc. It will be observed that the jaws open and shut horizontally, and that the
pressure is applied hydraulically, the electric current being turned on and off by means
of the foot pedal. There is, of course, a water circulation for cooling. The transformer
RESISTANCE WELDERS OF THE BRITISH INSULATED & HELSBY CO. 41
is contained in the cast iron base, and different tappings on the primary can he em-
ployed by meanB of the switch, shown at the left-band side, for work of different
chsractere. Eye-bolts are provided at the top of the casing, so that the whole plant
can be slung and carried to the point where it is desired to use it.
The machine shown in Fig. 27 differs from the foregoing in several respects. It is
smaller, for one thing, being only intended to deal with welds up to 2 square inches
in area, and the pressure is applied by the spoked hand wheels acting on a screw and a
serieB of levers. The current is turned on and off by means of the hand switch on the
left-hand side. The articles to be welded are gripped in the jawe by the two hand
vheels, and the jaw carriers, which are of stout proportions, are all of them provided
with water circulation. The machine is particularly intended for welding drills.
The manufacture of chains from coils of wire is carried out by two machines, the
first of which bends the links and threads them into a chain, while the second forms
Fio. 26.— B.I.W. Cham-Liuk-Fonniiig Machine.
the welds. Although the first machine does not correctly come within the scope of
this Work it is necessary to describe it, since the complete process cannot properly
be understood without it. Three sizes of machine are made. They deal respectively
with wires having diameters of from j^in. to ^in., ^^in. to^in., and ygin. to-j^in.
The smallest machine turns out from fifty to sixty links per minute, and takes from
1 to 2^ horse-power to drive it ; the middle size machine can make from forty to fifty
links per minute, and requires from 2 to 4 horse-power ; while the output of the largest
machine is from twenty to thirty links per minute, and a horse-power of from 3 to 7
is needed to drive it. One of the machines is shown in Fig. 26. The minimum propor-
tions of the links made on these machines are — length 5 diameters of wire, and width
3J diameters of wire. The machines are belt-driven and provided with fast and loose
pulleys. The control is by the hand lever seen at the right-hand or driving end.
There is also a foot-operated lever which is attached by chain to the hand lever, and
which, when depressed, throws the belt on to the loose pulley and brings into opera-
tion a brake which acts on the Sy-wheel, thus enabhng the machine to be stopped
42 ELECTRIC WELDING AND WELDING APPLIANCES
almost instantly in case of emergency. Power is transmitted to a back shaft through
a pair of double helical wheels. Mounted on the back shaft are three cams, the first
of which is a triple-path cam, which operates all the tools forming the links. The
centre path pushes forward the main slide, which carries a parting-off tool and two
bending tools, which form the link into a U shape from the back et the mandril. The
two side paths operate levers carrying the tucking tools, which close the Unk at the
front of the mandril. The second cam on the back shaft operates a gripping lever,
which holds the wire while it is being parted off. The length of the path of this cam can
be varied. The adjustment for gripping different diameters of wire is made by a screw
at the gripping end of the lever. The third cam operates the feed. It is made adjust-
able, so that any length of feed can be obtained to suit any link within the range of tiie
machine. From it the feed slide is operated through a bell crank lever, the feeding
end of which is fitted with a device which grips the wire on the feed stroke of the slide
and automatically releases it when the end of the stroke is reached. This gripping
device is fitted with a smaU cam which enables it to be thrown out of action at any time,
but the main use of which is to allow the machine to be started up and the motions
put into operation before actually starting to make chains. The cam is fitted with a
lever for finger and thumb operation, and should be put in action when the slide is on
the back stroke.
Running from the front to the back of the machine on the right-hand side is a shaft
driven from the back shaft through a pair of bevel gears. Mounted on it are two cams
and a spur pinion. The first cam operates levers which raise and lower the top mandril,
an operation which allows the formed link to be taken out by fingers. The second cam
is responsible for the in-and-out motion of the lacing spindle. The pinion drives a
spur wheel, in the face of which is sunk a cam path. From this path motion is given to
a quadrant which drives the lacing spindle in a semi-rotary manner. The semi-
rotary movement is done in two stages, each of 90 deg. The stroke of the lacing
spindle is adjustable.
The mandril is in two parts, upper and lower. The latter is stationary, and only
acts as a stop and stiffening block for the upper mandril, round the bottom end of which
the link is bent. A groove is formed down the front of the lever for convenience in
lacing. An adjustable cutting die is fitted so that the wire may be parted off clean.
On the extreme left of the machine is a straightening device.
In operation the first 2 ft. or 3 ft. of the coil of wire are straightened by hand, and
the end is threaded through the straightening rollers — ^which are slacked off for the
purpose — through the gripping device on the feed slide, and through the cutting die
until it — ^the end — ^projects through about J in. on the mandril side. The straightening
device is then adjusted, after which the fly-wheel is turned round until the shearing
tool cuts off the projecting | in. of wire. After adjusting the feed grip, main grip,
length of feed and stroke of lacing spindle to suit^the wire and link, the machine is
ready for work. The belt is first thrown on to the fast pulley. Then, when the feed
slide is on the back stroke, the small cam is slipped over and the feed grip thus put
into action. The machine then works automatically.
The cycle of operations is as follows : On the forward stroke of the feed slide the
wire is pulled through the straightening rollers and the end is fed behind the mandril.
As the slide reaches the end of the feed stroke, the main grip comes down and holds
the wire on the anvil. Meanwhile the back sUde is moving forward, and as soon as the
wire is gripped the shearing tool cuts off the length of wire necessary to form the Unk.
This piece of wire is caught by the back-bending tools and bent into a U shape round
the mandril. Next, the tucking tools come into operation and bend the ends of the U
44 ELECTRIC WELDING AND WELDING APPLIANCES
towards each other, thus completing the link. The lacing spindle then moves forward,
and the* fingers close on the completed link. As soon as this happens the top mandril
rises to allow the link to be withdrawn. When it is clear the mandril drops down and
the wire is fed behind for the next link. Simultaneously, the lacing spindle makes a
quarter of a turn, thus changing the position of the first link from the horizontal to the
vertical plane, and then moves forward again to enable the fingers to place the link in
the groove in the mandril. When the second link is formed it is threaded into the first
link. The fingers then retire and are again turned through an angle of 90 deg. to the
horizontal plane ready to take out the second link. The motions of the lacing spindle
are so arranged that the joint on every second link is on the same side, so that the chain
when being welded has only to pass through the welder twice.
We can now pass on to the welding machines, one of which is shown in the engrav-
ing Fig. 28. Three sizes of machine corresponding with the three sizes of bending
machines are made, and there is a modified form of each of the two larger machines,
but the modifications are only in detail. The three machines require from one-half
to 1 horse-power ; from 1 to 2 horse-power ; and from 2 to 3^ horse-power respectively.
The first can turn out from 15 to 20 links per minute, the medium-sized machine —
and our illustration shows one of them — ^from 10 to 18 links per minute, and the
largest machine from 5 to 8 links per minute.
Each machine consists of a cast iron stand on which i§ mounted a single-phase
transformer, and all the necessary working parts. Power is supplied by a belt drive
on to a fly-wheel pulley. Spur teeth, cut on the inner side of the fly-wheel rim, drive
a pinion and half clutch which runs loose on the end of a cam shaft. The other half
of the coupling slides along the cam shaft and is thrown into mesh by a hand operated
lever on the left-hand side of the machine. All the cams are mounted on the one shaft.
The welding electrodes are clamped in position on the front of the secondary casting.
The transformer is pivoted, and can be tilted forward by a cam to bring the electrodes
into contact with the link. A spring pulls it back after the welding of the link has
taken place. Each of the upsetting tools is operated by a separate two-step cam.^
The first step closes the ends of the link to make contact and the second upsets the
weld. When welding is complete the tools are opened again by springs. There are
swaging tools which are closed by cams and opened by a spring. Both sets of tools may
be adjusted. There is also a trimming tool for cutting off the fins which are left on
the links after swaging. It is operated through a bell crank lever actuated by a cam.
At the extreme right of the machine is the feed cam, which acts upon a lever. At
the feeding end of this lever is a pawl which engages the links of the chain on the feed
stroke, and slides over them on the return stroke. The length of the feed is adjusted
in the cam. When being welded the chain rests upon an adjustable saddle guide.
At the back of the machine is fitted a cam-operated automatic switch. A main
switch and a fuse box are fitted on the left-hand side of the machine. For regulating
the speed of heating at the weld, there is a 5-speed plug box at the back of the trans-
former. The front part of the secondary is fitted with four nipples to provide for the
cooling water circulation.
A fuU cycle of operations is as follows : (1) The automatic switch opens ; (2) the
weld is upset ; (3) the transformer tilts back ; (4) the weld is swaged, and the upsetting
tools release the link ; (5) the feed draws the next link into position ; (6) the fins are
trimmed off the link which enters the trimming-box ; (7) the upsetting tools close
the joint in the new link ; (8) the transformer tilts forward and causes the electrodes
to make contact at each side of the joint ; (9) the automatic switch closes and heating
commences ; and (10) the clutch is automatically thrown out.
46 ELECTRIC WELDING AND WELDING APPLIANCES
The company affirms that seam welding, the progress of which has been consider-
ably delayed owing to the war, but which is now being quickly developed, is un-
doubtedly the cheapest and best method of jointing thin material up to, say, No. 18
S.W.G. in thickness. With it welds can be made at the rate of 5 ft. per minute on
thin material — say. No. 33 S.W.G. — ^and at the rate of 1 J ft. per minute with No. 18
S.W.G., with a current consumption of one and fieven units per 100 ft. respectively.
A limitation of seam welding, however, is that, though there are cases in which a
machine may be used for welding different kinds of work, generally speaking, each
particular kind of work requires its own machine. Hence there are many different
types which, though they work on the same general principle, and have many parts
and motions in common, yet have their own distinctive features. It should be said,
though, that in many cases the variation is only in the form of the electrodes and of
the arms carrying them, the bodies of the machines remaining the same. A feature,
however, which we beUeve is common to all the seam welders made by the company,
is that the operator can sit down while working, it being recommended that the stool
should be about 22 in. high, and placed in such a position that each of two pedals
may be easily reached. The left pedal operates the top electrode arm, and it applies
pressure for congoUdating the weld. It also automatically switches on the current
when the pressure applied reaches the required amount. The right-hand pedal, on
the other hand, controls the driving clutch and thus causes the electrodes to revolve.
There are other points which all the machines have in common. For instance, the
electrodes may be run at different speeds by means of cone pulleys, and it is also
possible to obtain four different heating speeds by means of a plug box. We illustrate
three examples of these machines in Figs. 29, 30, and 31.
Figs. 29 and 31 show two views of what is known as Welder No. 60, one of them —
that given in Fig. 29 — ^provided with a circular seaming attachment, and the other
with 20 in. longitudinal stakes. The body of the machine shown in the two views is
the flame. It is only the electrodes that are altered. Machines of this type are intended
for a large number of purposes, including the production of paint drums, canisters,
kettles, oil-cans, milk-cans, etc. In each case the electrodes consist of copper rollers
which are driven at definite speeds by means of chain gearing, provision being made
to vary the speeds to suit the material being welded. Special bearings are provided
so that the passage of the current through them does not interfere with their mechanical
function, and they are kept cool by a water circulation system. The pressure applied
to the rollers is adjusted by means of a compression spring at the back end of the
upper electrode. The machhies are power driven and require about a half horse-power.
The primary winding has four tappings so that four welding currents are obtainable.
Fig. 30 shows Welder No. 61, a machine which is very similar to the foregoing,
and which is especially designed for welding the spouts on to kettles. Its general design
and method of working are so evident from the illustration that no description appears
to be necessary. It is intended to weld iron or mild steel sheet up to ^ in. added
thickness.
In all cases the article to be welded is placed on the bottom electrode in such a
position that when the top electrode is brought down, by depressing the left pedal,
it makes contact exactly where it is desired to make the weld. In some cases the
article is clamped when in its correct position. As soon as contact between the upper
electrode and the work is made, further pressure is exerted to switch on the current,
and at the same time the right pedal is depressed so as to set the electrodes revolving
for the purpose of carrying the work around the bottom electrode. In some cases the
work is actually taken round with the lower electrode.
RESISTANCE WELDERS OF THE BRITISH INSULATED & HELSBY CO. 47
The company makes spot welders in five sizes, according to the thickness to be
welded. Standard machines are made for welding the following added thicknesses :
0.16 in., I in., J in., | in., and | in., the ma^nmmn current required varying from 6 to
30 kilowatts. For different classes of work a large number of different designs is
made. For instance, the arms, or stakes, as the company calls them, are made in
lengths varying from 9 in. to 36 in. Fig. 32 shows a group of what are known
as No. 13 spot welders fitted with different length stakes. These particular machines
are intended tor the welding of iron, or mild steel sheets up to J in, i^^regate thick-
Fia. 32.— Group of B.I.W. No. 13 Spot Weldeia.
nesB — though they may, we gather, be used intermittently for sheets up to gin.
aggregate thickness. The top stake is fitted with a swivel joint, and the bottom stake
can be fixed in any desired position on the face plate. The welder is foot operated.
Depressing the pedal brings down the top electrode into contact and switches on the
current. Directly welding temperature is reached, additional pressure on the pedal
cuts off the current while still maintaining pressure on the weld and consolidating
it. The electrode tips are water-cooled and are renewable. By means of four tapping
plugs, four heating speeds for varyii^ thickness of work are obtainable.
Some of the spot welders which the firm makes are operated by hand-lever, and
48 ELECTRIC WELDING AND WELDING APPUANCES
some — the larger sizes — by means of a spoked wheel. In such machines two operators
are required. In some machines, too, the current is cut on and off by hand, the switch
not being interlocked with the pressure-applying system.
In all types and sizes the method of working is practically identical, and as we have
already described it, with, of course, slight variations necessitated by the differences
in arrangement to which we have already alluded. The actual time occupied in
welding may vary from a fraction of a second in the case of the thinnest material
up to, say, 40 seconds ^with the thickest metal. The current consumption may
similarly vary from, say, one-quarter of a unit for 1000 welds with thin sheets up to
330 units per 1000 for the heaviest material. The speed of working varies, of course,
with the type of machine, the thickness of material, and the personal equation of the
operator. In one case, we understand, an operator using a small machine has made
as many as 12,000 welds during a T^-hour day. On larger machines the output is, of
course, less.
As giving some idea of the different kinds of articles which are being successfully
welded by means of this company's spot welders M'e append the following list :
Fittings to enamelled hollow-ware ; tanks ; pulleys ; straight sheet iron tubes, and
elbows ; spades, shovels and trowels ; automobile and bicjxle parts,' mud -guards,
bonnets, fittings to chassis, etc. ; machinery guards ; sheets and expanded metal to
flat and profile iron for shelves, lockers, etc. ; agricultural machine parts ; fuse parts ;
fan propellers ; tin ware ; lattice for reinforced concrete, etc.
CHAPTER VIII
MACHINES AND APPARATUS FOR ARC WELDING
In an earlier chapter we explained that, for arc welding, the only absolutely essential
accessory, in addition to the electrode and holder, was a resistance to go in series
with the arc. The only other thing necessary is a supply of current at a suitable
voltage. Some consider it desirable to have an ammeter in the circuit, but in many
cases instruments of all kinds are dispensed with for the actual welding circuits. Now,
although the absolute essentials are only as set out above, yet it is highly probable
that in practically every case some additional arrangements beyond those actually
existing in any given works will have to be made in order to obtain current of the
desired character and pressure. In the large majority of cases in this country, at any
rate, direct current is used for arc welding. If the available electric supply be alter-
nating, there will have to be a motor generator to convert the energy into direct
current. If, again, the available supply be direct current, but of a voltage in excess
of that required for the welding circuit, it will also be necessary to have a motor
generator or a rotary motor converter to reduce the pressure. Many firm^ make motor
generators which are suitable for arc welding circuits, and among them we may
mention the following : The British Electric Plant Co., Limited, 78 St. Vincent
Street, Glasgow ; The British Westinghouse Electric and Manufacturing Co., Limited,
Traflford Park, Manchester ; Crompton and Co., Limited, Chelmsford ; The Electric
Welding Co., Limited, 28 Basinghall Street, London, E.C. 2 ; J. H. Holmes and Co.,
Newcastle-on-Tyne ; The Lancashire Dynamo and Motor Co., Limited, Traflford Park,
Manchester ; Mather and Piatt,* Limited, Manchester ; Mavor and Coulson, Limited, of
Glasgow ; Bruce Peebles and Co., Limited, East Pilton, Edinburgh ; The Phoenix
Dynamo Manufacturing Co., Limited, Bradford ; The Premier Electric Welding Co.,
Royal Liver Building, Liverpool ; The Rees Roturbo Manufacturing Co., Limited,
Wolverhampton. Some of these firms make motor generators for converting alter-
nating into direct current ; some machines for reducing direct current voltage, while
some of them make both types of machines. All the machines can be used in aro
welding, though in some cases they are simply combinations of standard motors and
dynamos made by the various firms. In other cases, however, they embrace machines
specially designed to produce certain specific effects, and to some of the latter we
shall refer in what follows. Some of the firms, too, are prepared to supply portable
self-contained arc welding generating sets which can be readily moved about from
place to place as may be required, and are able to start producing current at a moment's
notice. We shall have occasion to refer to machines of that type also.
First of all we may deal with some of the apparatus supplied by the British
Westinghouse Company. A business-like self-contained arc welding equipment,
embodying some of this firm's machines, is shown in Fig. 33. The plant, which, as will
be observed, is mounted on the platform of a motor lorry, and which is ordinarily
protected by a covering which can be lifted oflf when degired, as shown in the
engraving, was built to the order of The British Arc Welding Company (Bristol
Channel), Limited, of Cardiff, a firm which concerns itself largely with shipbuilding
E.W. B
MACHINES AND APPARATUS FOR ARC WELDING
51
and other repair work. The generator, which is of 26 kilowatts normal output, and
which is designed to permit of working multiple arcs in parallel and intermittently
when using either carbon or metallic electrodes, is driven by a petrol engine designed
to develop some 55 horse-power when running at a speed of 1160 revolutions per
minute. The generator is intended to permit of Satisfactory operation over a con-
siderable regulation curve, thus allowing a variety of work to be carried out economi-
cally. The direct coupled exciter also provides current for lighting, and for driving
portable grinding or driUing machines.
This firm builds machines with a special winding which has for its object the doing
away with the necessity for using a resistance in the welding circuit or, in other words,
so controlling the working of the machine that injurious rushes of current are impos-
sible. The winding which, we understand, was designed by the company in co-
operation with Mr. H. S. Marquand, is shown diagrammatically in Fig. 34. There
To Article
to be <
Welded
-^VVSAAA/N/VVV
-ZTT
p =
A^
Commutating Poles
Series iVinding
Shunt Winding
Separately Excited Winding
Voltage Regulator
connected In Shunt
'The Enoincer"
.Welding Current Regulator
Connected in separate
excitation circuit
SwAin So.
Fig. 34. — Diagram of Connections of Westinghouse Generator for Arc Welding.
ajre three separate windings, or four, if that of the commutating poles be taken into
account. The series and commutating pole windings — ^A and P respectively — ^are in
series with one another, and, of course, with the armature. The shunt winding B is
connected not across the armature alone, but across the terminals of the msu^hine, and
hence outside the series and commutating pole windings. It has an adjustable resist-
ance in series with it. There is a further winding C which is separately excited from a
constant voltage exciter, and which also has an adjustable resistance in series with it.
The windings B and C assist one another while winding A opposes both of them. When
considering the effect of these three windings the demagnetising effect of armature
current must not be lost sight of. Let us suppose that the machine is running at fuU
speed, but with open circuit. Then the series winding is practically inoperative, since
it is only carrying the comparatively negUgible current required to energise the shunt
winding B. On the other hand, the latter winding is fully effective, and the winding
C is energised to give in conjunction with winding B the desired initial voltage on the
armature. -If now the electrode, that is to say, one terminal of the generator, be
62 ELECTRIC WELDING AND WELDING APPUANCES
m
brought into contact with the '' work," which is connected to the other terminal, the
tendency is, naturally, for a heavy current to flow through the armature and the
series winding A. As soon as current begins to flow, however, the demagnetising
effects of the series winding and of the armature reaction tend to reduce the armature
voltage, the amount of reduction depending, of course, on the relative strength of the
series field and the combined shunt and separately excited windings. But this is
not all that happens, for, since the generator terminals are short circuited, the shunt
winding B is also short circuited, and becomes non-effective. Hence, the separately
excited winding C is then opposed by the series winding A and the armature reaction,
and matters can be so arranged that the short circuit current will be actually less than
the normal full load current of the machine. In practice, of course, the actual time
during which the machine id short circuited is only under ordinary working conditions
for a fraction of a second, but even if by accident the short circuit period is prolonged,
no harm can happen to the machine, and in working ne steadying resistance is
required in series with the arc. As the makers point out, this means a considerable
reduction in the power consumed, since all the C^B losses in the resistance are
avoided. It is of interest to see to what these losses amount.
Let us suppose, say, that a welder is taking current from a 100- volt generator.
If he be using a metal electrode, the current may be between 50 and 200 amperes. Take
it that the average is 125 amperes. The voltage across the arc may be, say, from 25
to 40. Let ud take the best case as far as losses are concerned, and imagine it to be 40.
That means that the resistance is absorbing 60 volts. The energy being consumed in
the resistance is, therefore, 125 by 60, or 7500 watts, while the energy in the arc which
is doing the welding is only 1 25 by 40, or 5000 watts. More than half of the total energy
in the circuit is therefore absorbed in the resistance. Of course, this does not quite tell
the whole tale, for the energy consumed in the exciter of the protected machine has
to be taken into account, but the loss in that machine id small compared with the loss
in the resistance. Moreover, the loss is, of course, greater if a higher voltage than 100
be used. With a carbon arc, if we take the figures of the Steel Barrel Company,
limited, of Uxbridge, to which reference has been made in an earlier chapter, the
initial voltage is 90, and the voltage across the arc from 50 to 55. Taking the higher
figure, as was done in the case of the metal arc, the voltage absorbed is 35, so that
whereas the arc, with a current of 300 amperes, absorbs 300 by 55, or 16,600 watts,
the resistance loss is only represented by 35 by 300, or 10,500 watts.
Thus in the two cases we have taken, whereas with metal electrodes the ratio of
energy wasted to energy usefully employed in the arc may be as 7.5 to 5, with a carbon
arc the ratio is as 10.5 to 16.5. In both instances the losses are heavy, but proportion-
ately the carbon arc system appears to be the less wasteful.
Let us attempt to get some idea of what this waste means in pounds, shiUings and
pence. Suppose for the sake of argument that a carbon arc welder works eight hours a
day, and that he is actually using his arc for only half that time, say, four hours for
five days a week and two hours on Saturdays, a total of twenty -two hours per week.
During that time the energy waited in the resistance will be 10,500x22=231,000
watt-hours, or 231 Board of Trade units. Taking the cost of the energy at Id. per
unit, there is, hence, a loss of nearly £1 per week, or, say, £50 per year for each welder.
These figures become worse the greater proportion of his working time the operator is
using his arc, and if he were actually welding during the whole of his time the annual
loss per man woald, on the basis of calculation we have taken, be over £100.
By means of the two adjustable resistances in the Westinghouse-Marquand
arrangements, the current flowing in the arc can be varied within certain limits, so
si
•
00
1
o
O
O
o
•a
8
I
s
h
64 ELECTRIC WELDING AND WELDING APPUANCES
that the same machine can be used for different kiiidB of welding work calling for
CQirents of different strengths. In addition to this means of control, ve understand
(hat slterstion of the brush positions affordb a further means of regulation. The com-
mutation is said to be sparkless tmder practically any brush position. Sets of this
type have been successfiiUy arranged on boats, so that work can be carried on from
the water, an arrangement which in ship repairing is sometimes most convenient. The
generators are rainproof, since they may frequently be called upon to run continuously
for long periods under conditions of weather and position which may be anything
but good.
Going back to the plant illustrated in Fig. 33, it may be mentioned that each lorry
is provided with 550 yards of cable, so that current can be conveyed for that distance
away from the point at which the vehicle
is stationed. The cable has cab-tyre
sheathing and is carried on rollers in
damp ■ proof boxes mounted on the
chassis. The lorry can carry some 150
gallons of petrol in its tanks. The
tank, which is seen mounted above the
generator, is kept full by pumping up
from a larger tank arranged beneath
the chassis.
Another self-contained welding set
of a similar character is Bupplied by the
Premier Electric Welding Company, of
Royal Liver Building, Liverpool. It is
shown in Figs. 35, 36 and 37. It also
can be mounted on a lorry or in a special
hut of its own, which can be slung on
shipboard and lowered on to the deck
V)r into a hold (see Fig. 36). The set was
specially designed for use with the metal
arc process. It consists of a 10-brake-
horse-power petrol engine, direct coupled
to a 4.3-kilowatt generator with a sepa-
FiG. 36.-Premier Welding Set in Cabin. rate exciting dynamo connected to the
some shaft and mounted on a common
bed-plate. The main generator has three windings— a series winding, a shunt winding
connected across the armature, and a separately excited winding. The two latter
assist one another, while the series winding opposes both of them. The combined
effect of the shunt and separately excited winding produce a field strength which
determines the voltage of the generator before the welding arc is established. When
the arc is struck, however, current flows through the armature and the series
winding, with the result that the strength of the field is reduced and the voltage
in consequence lowered. When the combined effeot of the series winding and the
armature reaction is sufficient to balance the counter-effect of the separately excited
winding, the resistance drop of the external winding of the generator will then
determine the voltage of the generator terminals. The makers point out that
with a separate exciter maintaining a constant current, the armature current of
the main generator must necessarily remain constant in order to keep the armature
reactance and the differential series field constant. This gives a machine with an
56 ELECTRIC WELDING AND WELDING APPLIANCES
external current characteriHtic which is nearly constant within the limitation of
the welding voltage.
In opere>tion a reactance is used in series with the arc on the negative leg of the
generator. This reactance has four terminals, which are so connected to the two ter-
minals of the welding circuit and to the terminals of a three-pole double-throw &^«-itch
that in one position of the latter the two coils of the reactance are connected in parallel,
whilst in the other position they are in series with the generator and the welding arc.
It is claimed that a reactance and switch so arranged in connection with a generator
wound in the manner above described enable an operator, without having to change
the generator ipeed or any of the connections, to arrange simply by throwing the
switch over in one direction or the other to provide either a small current for welding
small articles and building up thin and worn plates, or a larger current for use in con-
nection with heavier work.
Fig. 38.— LaucaBliire Dyiiamo and Molor Compauy's Arc Welding Set.
Another differentially wound generator, specially intended for electric arc welding
work, is made by the Lancac^hire Dynamo and Motor Company, Limited, of Trafford
Park, Manchester. It is shown coupled direct on the same bed-plate to its motor in
Fig. 38, while a diagram of the windings of the two machines is given in Fig. 39. As
will be observed, the arrangement of the winding is different in several particulars
from the windings oi the machines which have been described above. There is a shunt
winding A which is connected across the armature of the generator, and has a regulator
in circuit with it, and a series winding which is in the are welding circuit, and there
is a third separately excited winding B which, however, is arranged in series with the
field winding of the motor across the supply mains.
In describing the arrangement the makers write as follows ; " The arc may be
struck across the armature of the generator without any resistance in circuit, and
the plant is capable of running for short periodp with the armature of the generator
short circuited." The windings A and B tend to assist one another, while the winding
C opposes both, and hence tends to lower the generator voltage. No series resistance
MACHINES AND APPARATUS FOR ARC WELDING
57
is used in the welding circuit. At the moment of touching the work with the electrode
there is a tendency for an excessive current to flow in the generator circuit. This
current, of course, flows through the series winding, and is limited to the value which»
will demagnetise the generator field by an amount sufficient to prevent any larger
current from flowing. Similarly, when an arc is struck, the resistance of the circuit is
increased, and the current tends to fall. This tendency is compensated for by a
diminished demagnetising effect of the C winding, whereupon the generator voltage
is increased to an amount which will permit of the flow of the desired current."
/
irnH
Motor
Field
Winding
"b"
Winding
Starter
A
Winding
r< Shunt
< Regulator
\ Supply
I to A re
• ••
C Winding
J
'the EnQineer" Swain SO
Fig. 39. — Connections of Lancashire Dynamo and Motor Company's Arc Welding Set.
CHAPTER IX
MACHINES AND APPARATUS FOR ARC WELDING (continued)
As an example of apparatus particularly suitable for arc welding we may at this point
refer once more to the diflEerential electro-magnetic clutch devised and patented by
Messrs. Walter L. Davies and Alfred Soames, both of Faraday House, 66 Southamp-
ton Row, Holborn, London, which was described at some length in the issue of
The Engineer of January 25th, 1918. The advantages claimed for this device, for
which the Equipment and Engineering Company, has acquired the exclusive licence
in the United Kingdom, are, as far as electric arc welding is concerned, as follows : —
(1) Any dynamo giving Sufficient power and driven from any suitable source of
power may be used, its characteristics being so altered as to make it suitable for the
work.
(2) The maximum current to be taken can be set at any value within the limits
of the dynamo.
(3) When the apparatus has been set for any desired current the latter will remain
practically constant from short circuit to the maximum length of arc that the volts
will maintain. There is no necessity to " snatch at " the arc when striking it. The
electrode can be rubbed on the work, and the arc drawn cut as desired. A short arc
does not produce a rise of current and consequent burning. The operator is thus
enabled to give his full attention to the work, since the arc cannot '" run away from
him." There are no jumps or breaks in the current.
(4) No resistance is required in the welding circuit, and consequently the whole of
the watts generated are used upon the work.
The clutch is shown in Fig. 40. It may be placed either between 'a motor and a
generator, as shown in Fig. 41, or between a steam engine or other prime mover and
a generator. A is the driving shaft and B the driven shaft, which is coupled direct
to a separately excited dynamo. Keyed to the shaft B is a coupler D, which is furnished
with driving-pins H. Housed in the coupler is a Skefko bearing C, which receives
the end of the shaft A. Near the end of the shaft A is another Skefko bearing E, which
is housed in a disc G, to the periphery of which is bolted a cast-iron ring F, the disc
G and the ring F forming the transmission momber of the clutch. In the disc G,
-arranged at similar intervals to the pins H on the coupler D, are holes in which are
inserted leather rings J, the latter also being pierced with central holes to accommodate
the pins H. The disc G and the ring F are free to float and move to the extent per-
mitted by the Skefko bearing. The body of the clutch is indicated by the letter K,
and the magnetic circuit is completed by the ring L.
There are three windings. A, B and C. Fig. 42 is a diagram showing the basic
principle of the application of the clutch to a motor generator when the apparatus
is used for electric arc welding, and Fig. 43 shows the electrical connections. In both
these cases the clutch is, of course, only shown diagrammatically. Coils A and C are
made up of many turns of fine wire, while coil B consists of comparatively few turns
MACHINES AND APPARATUS FOR ARC WELDING 59
of thick wire. No part of the clutch moves longtitudinally, bo that its reluctance
remainB constant and the variation of the magnetism produced by the coils varies the
pressure of the clutch members against one another only.
The action of the clutch is as follows : The coil A is energised either from the
mains which supply current to the motor, or, if an alternating current motor be used,
from a small exciter on the driving shaft. The coil is so proportioned as to produce
an initial pressure of the clutch members, which is more than sufficient to transmit
the load. Coil B is connected in series with the armature of the dynamo on the driven
shaft, and its polarity is such as to counteract the eflect produced by the coil A. That
is to say, as the current in the coil B increases, as it does when the load on the
driven machine increases, the pressure of the clutch members against one another
decreases, until a point is reached when the pressure is only just sufficient to transmit
Fig. 40.— The Davies-Soames— Day sohms— Electro- Mtgnetic Differential Clutch.
the load without slippii^. If that point be passed the clutch slips. It is apparent,
therefore, that the current taken from the dynamo cannot pass a given maximum
even if the machine be short circuited. The particular maximum to be reached can
be arranged by adjusting the excitation of the coil A with a rheostat.
The coil C, which, like coil B, opposes and tends to weaken the effect produced
by the coil A, is connected across the brushes of the driven dynamo. In a separately
excited dynamo the torque required to drive it at any speed is proportional
to the current taken from the dynamo, irrespective of the speed and volts. If a con-
stant current be taken, it requires a constant torque to drive it at any speed in a fixed
field. It is to counteract the variation in the coefficient of friction that the coil C was
added to the apparatus. On open circuit the coil A gives an initial pressure or attrac-
tion between the members of the clutch. The coil C, which, as explained above, is
Arranged across the brushes of the dynamo, reduces the pressure produced by A.
If current be now taken from the dynamo the coil B still further reduces the pressure
AUCHINES AND APPARATUS FOR ARC WELDING
61
or attraction between the clutch members until a point is reached when the clutch
slips. When slip occurs, however, the volts of the driven dynamo decrease, and,
consequently, the effect of the coil C is weakened, which is equivalent to increasing
the effect of A. By this means the slip is prevented from increasing unduly. Should
the current taken from the dynamo tend to increase, the action of the series coil B
would decrease the pressure attraction between the two clutch members. As a net
result, therefore, the coils B and C adjust the pressure, so that no matter what is done
with the arc, the current remains practically constant. By suitably proportioning
the ampere turns in coils A and C, which may be done by means of rheostats in series
with them, any desired characteristics, within reasonable limits, may be obtained.
Tmc Encinccr"
Fig. 42. — Davies-Soanies Chitch arranged for Arc Welding.
The clutch, therefore, can be used for driving a dynamo the current from which is
being used for light or heavy work.
We may add that since our description, of which the foregoing is an abbreviation,
was published, and, indeed, since the earlier chapters of this book were penned, Messrs.
Davies and Soames have made sundry modifications of their device, which, they
claim, have increased its efficiency. For example, they have altered the shape of the
magnetic circuit of the clutch, with the result that there is less leakage of lines of force
and a higher efficiency is arrived at. Moreover, they have succeeded in reducing the
electro-motive force of the welding circuit to as low a figure as 33 volts. We have
watched the apparatus in operation with that voltage, and observed that, as might be
expected with such a low pressure, it was quite impossible to have a long arc, with
its accompanying disadvantages. At the least attempt to draw out the arc beyond
a certain point the circuit was interrupted. On the other hand, a skilled operator
appeared to have no difficulty whatever in maintaining an arc and in doing excellent
62
ELECTRIC WELDING AND WELDING APPLIAXCES
welding with a current that only yaried within Bmall Hmitg, the wcvk prodooed
of an even charaeter. A coated metalfic electrode was, of coarse, being used. It
should be mentioned, in conclo8ion,that Messrs. Davies and Soames now use a reactance
m the welding drcuit.
While on the subject of special windings, attention may be drawn to an article
which appeared in the December, 1918, issue of the Am^can General Electric Review^
and was entitled "The Constant-Energy Arc-Welding Set.'' The article was written
by Mr. P. O. Noble, of the Direct Current Engineering Department of the General
Electric Company of Schenectady. The author takes for his text that '* all will agree
Dynamo JSL
Motor
Spindle \
Separately Excited
From Moto r Circtnt or
small Exciter tn case
of Alternating Current
Motor.
When the polarity of Coil
A is -i-.the polarity of B
and C are —
Bt C »ork against A.
Dy^ Field
Separately Excited From same source as Coil A.
A is constant, a Fall oF Volts across C. Increases pressure oF Clutch
a rise oF Current in B. Decreases . •*
Swain Sc.
Fia. 43. — Diagram of Connections of Davies-Soames Clutch.
that the ideal condition for a homogeneous weld on a given piece of work is obtained
when the voltage and the current at the arc are constant," a condition which is, he
maintains, impossible with the manually controlled arc. Hence the raison cTetre of
the machine which he describes, the principal advantage claimed for which is that it
facilitates the maintenance of a short arc and makes it difficult to obtain a long one.
Mr. Noble explains that the rate of consumption of electrode material is proportional
to the current in the arc and is independent of the voltage across the arc. ^^ In the
constant-energy system," he continues, '' when the operator shortens the arc, the
current increases and the rate of wire consumption increases, thereby tending to bring
the arc length back to normal. If he lengthens the arc, the current decreased and the
MACHINES AND APPARATUS FOR ARC WELDING
63
rate of wire consumption decreases. This automatic action tends to maintain the arc
at the proper length. If the arc is unduly lengthened, the current will decrease until
the electrode does not fuse properly and the arc will go out. In the constant-current
system, the rate of wire consumption is constant, and there is no such corrective effect
as that just described. This system also makes possible the maintenance of a long arc
with the consequent deposition of a large amount of highly oxidised and porous metal.
Ser/es
Ffeid
i^/^/\fdiQ^^LU^Jm/\^^
Comm Motor
Field Armature
Comm
Field
Generator
Armature
The Enoincer"
Fig. 44. — Electric Connections of Constant-Energy Balancer Set
Swain Sfr
The oxidisation is evidenced by the fact that with a long arc there is present, in addition
to the black oxide of iron — ^Pg O4 — which is present on all bare wire welds, an abun-
dance of red oxide of iron — Pcg O3 — showing that the metal is more highly oxidised
in passing through the arc."
The constant-energy balancer set consists of a direct-current motor mechanically
connected to a direct-current generator. The electrical connections of the two machines
are shown in Fig. 44. It will be observed that, in addition to being mechanically con-
64 ELECTRIC \\T:LDING AND WELDIXG APPLIANCES
nected, the motor and generator are ako electrically connected in series across a supply
circuit of constant potential. One terminal of the welding circuit is taken from the
connection between the two armatures, and the other terminal from the positive
line. The polarities of the motor and generator are so arranged that the armature
currents of the two machines add together in the welding circuit, which, Mr. Noble
remarks, makes possible an approximate 50 per cent, reduction in the size of the units
involved. No series resistance is used in the motor, generator, or welding circuits,
the difference between the supply voltage and the arc voltage being absorbed by the
motor. This, adds Mr. Noble, '' results in saving the power which is usually wasted
in rheostats. The ratio of the energy at the arc to the input to the set is 66 per cent.
With the ordinary set of corresponding capacity using series regulating resistance, this
ratio is approximately 22 per cent."
The initial voltage for striking the arc, and the average current for the particular
work in hand, may be regulated at will by means of the motor and generator field
rheostats, and by means of the switch which changes the number of effective turns in
the differential series field winding of the generator. Changes of current may be
obtained, it is stated, from 40 to 150 amperes by very small increments. After the
arc is established, the variations in current and voltage at the arc with changes in
the relative positions of electrode and work, follow, approximately, a constant energy
law. The regulation is entirely inherent in the set itself, and is accomplished without
the use of energy-consuming resistances or vibrating regulators.
Mention may also be made of a rotary motor converter or self-contained rotary
transformer, which is made by the Equipment and Engineering Company, of 2 and 3
Norfolk Street, Strand, London, W.C. 2. The machine has a single field and a single
armature, the latter being furnished with a double commutator. The motor side is
arranged to absorb current at 500 volts, and the generator side to deliver current at
from 80 to 100 volts. The current available for the welding arc is 250 amperes for
steady working, but it can be raised by 50 per cent, or to 375 amperes for short periods.
The machine is of the semi-enclosed type, and is fitted with carbon brushes. It is
especiaUy intended for use in traction work in which the working voltage is in the
neighbourhood of 500.
CHAPTER X
MACHINES AND APPARATUS FOR ARC WELDING {continued)
Large numbers of portable generating sets designed for arc welding in works and
shipyards have been supplied by J. H. Holmes and Co., of Neweastle-upon-Tyne. The
particular arrangement adopted by this firm is shown in Fig. 45.* The generating
plant consists of a four-cylinder petrol engine of 28 brake-horse-power running at
850 revolutions per minute, coupled to a direct current compound wound dynamo
having an output of 250 amperes at 66 volts. This voltage, it will be noticed, is con-
siderably lower than that employed in some cases of arc welding. The plant is
mounted on a combined bed-plate, and has a special framework which enables the
equipment to be easily lifted and moved from place to place. On the framework is
also fixed a radiator for cooling the circulating water, the air being drawn through it
by means of a fan driven from the dynamo shaft. There is also mounted on the frame-
work a small switchboard carrying a single pole switch, double pole fuses, shunt
regulator, volt meter and ammeter. The special resistance used in conjunction with
this plant is shown in Fig. 46. It has four switches mounted on a sjiate base in front
of the resistance. The four switches have capacities of 100, 75, 60 and 25 amperes
respectively. The resistances are so connected up that it is possible by different
combinations of the switches to obtain currents of from 25 up to 260 amperes in ten
steps of 25 amperes each. The resistance is built up of cast iron grids, having the
firm's patented stiffening arrangement, which strengthens the grid and, it is claimed,
makes it absolutely rigid, thus preventing breakages due to movement or vibration.
Numerous self-propelling arc welding equipments have been supplied to ship-
building and arc welding companies in London, Belfast, Cardiff, Glasgow, Liverpool,
South Shields, etc., by Tilling-Stevens, Limited, of Victoria Works, Maidstone. This
company has developed three types of equipment, in each of which the vehicle is self-
propelling, and is driven by the well-known petrol-electric combination which is
associated with the name of the firm. In the first case the vehicle has an ordinary
lorry type body on which, at the back of the driver's cab, is a compartment for
containing the control gear and equipment, thus leaving a large proportion of the
platform free for ordinary carrying purposes. In another form, which we gather is
the more popular of the two, the vehicle is provided with a box-type body, which
serves as a workshop and a mess-room for the operators, as well as for containing the
welding gear and accessories. This type of vehicle is frequently fitted with a petrol-
driven air compressor for driving pneumatic tools. Both of these equipments are
intended for supplying the current for one arc only. In the third equipment arrange-
ments are made for supplying two arcs, one of which derives its current, as in the case
of the first two, from the main dynamo, which also serves to propel the vehicle through
* In a letter to the Editor of The Engineer dated April 23rd, 1919, and published in the issue of
that Journal of May 2nd, Mr. J. E. Weyman of Newcastle-upon-Tyne pointed out that the illustration
shown in Fig. 45 appeared to represent a set which he designed and supplied to the British Arc Welding Co.,
Ltd., and of which, with some modification, he had since supplied some eight further examples, for all of
which Messrs. J. H. Holmes and Co. supplied him with the electrical outfit.
E.W. F
MACHINES AND APPARATUS FOR ARC WELDING 67
the intennediary of a motor, while the other derives ita current from a small separate
direct-coupled petrol-electric generating set. Exterior and interior views of one of
the second type of equipments are given in Eigs. 47, 48 and 49, while an exterior view
of another design is given in Fig. 60. The chassis in all three coses is the same as that
of the firm's 40 horse-power standard vehicles. The prime mover is a 40 horse-power
petrol engine, which is direct coupled to an electric generator, designed to give 80 to
100 volts, and compound wound to give a level or slightly falling voltage curve. For
propelling the vehicle tMs machine, of course, supplies current to the motor, which in
turn drives the back axle through a cardan shaft and worm gearing. The control of the
Fro. 46.— Holmes Beeietance Frame for Arc Welding.
vehicle when travelling on the road is effected by means of the engine throttle and a
resistance, which varies the strength of the generator and motor fields, the entire rai^
of speed being controlled by the throttle pedal and resistance lever. The body is of the
box type, and is provided on the near side with hinged doors for lighting and ventila-
tion, and on the off side with one window and louvres. The driver's cab is boarded
up on the off side, and there is a lunged door on the near side. A sheet-steel weather
screen is also provided. At the back of the cab folding doors give the driver access
to the welding control gear, so that he can manipulate it from bis seat. In the interior
of the body, on the near side, there is a-locker seat extending for about half the length,
and a bench fitted with a vice, and provision underneath to contain cable for con-
veying current to the welder — and pneumatic hose if a compressor is fitted — occapies
the remaining space on that side of the body.
MACfflNES AND APPARATUS FOR ARC WELDING 69
The switchgear and resistances for the welding circuit are fitted in the front
portion of the body on the off side. The oablee from this gear run down through the
floor to terminals on either side of the body. From these terminals the cables can
be taken to where the are is required. The welding leads are supplied in convenient
lengths, which can be thimbled together as required, and junction boxes are provided
for the insulation and protection of temporary connections.
The plant is designed to weld mild steel plates from J in. to 2 in. thick and upwards,
and for all descriptions of steel and iron forgings and castings. The output of the
dynamo is from 18 to 20 kilowatts. When the car has been taken to the place where
the repairs are to be carried out, the controller-lever on the steering column is put into
the neutral position, and the main switch on the welding switchboard is closed. The
Fio. 48.— Tilling-StevenB Arc Welding Lorry— Interior.
motor is then entirely out of the circuit, and the engine and dynamo are set ready for
generating current for welding.
Another firm which has specialised in the manufacture of machines for supplying-
current for arc welding is that of Crompton and Co., Limited, of Chelmsford, and it
has turned out some large machines for this particular class of work. It makes
machines of various types, from those designed to keep one single arc going to those
intended to supply current to several separate welders working in parallel, each with
his own steadying resistance. Such generators as the latter are simply compoimd
wound, so as to give a level characteristic and to ensure stability. They do not differ
essentially from ordinary compound-wound dynamos, and do not therefore call for
special comment or for more detailed reference. Single welder machines, however, may
sometimes be compound wound so as to give a faUing characteristic, that is to say,
be oyer compounded so that increase in current tends to reduce the voltage, or they
may have three windings, one of them energised from a separate exciter. Then,
again, the machines may be motor -driven, the motor being either for alternating or
direct current. All the Crompton machines intended for arc welding purposes are, so
70 ELECTRIC WELDING AXD WELDING APPUAXCES
we nnderBtand, demgoed to withstaod overloads of 25 per cent, for two hours, 50 per
ceat. for short periods aod 100 per cent, momeatarily. To make a provisioD of this kind
is distinctly wise, because the dnty of a welding generator is witbont doabt extremely
udDOdfl, since the load is s very varying quantity. la the case of a small generator,
supplying only one welder, the variation may well amount, momentarily, to overloads
of twice the normal, the load rising instantaneoDEtly from zero value.
Two machines have been chosen to illustrate the special ptodocts of the Crompton
firm. Th^ are ahown in Figs. 61 and 52. The former shows a petrol-driven self-
ocHitained welding set, the engine, petrol tank, oil tank, radiator, generator and switch-
board being mounted on one bed-plate, so as to be readily portable. The generator
is otmipound wound to give any desired voltage characteristic, and is of 5 kilowatts
capacity at 110 volts when running at 1500 revolntions per minute. The machine
Fio. 49.— Tilling-SteveDB Ak Welding Lotty— Driver's SeaL
shown in Fig. 52 is a motor generator of 12 kilowatts capacity at 60 volts. The motor
is of the three-phase type, and the direct-current generator has three windings and a
separate exciter, so that effects which have been discussed in an earlier chapter in
connection with other machines are obtainable.
As examples of some of the electrode holders for metal or carbon electrodes now
being used, we may draw attention to Fig. 53, which shows two types of holder.
That on the left is intended specially for use with metal electrodes up to No. 6 gauge,
and in it the electrode is gripped by spring action, and there are no binding screws to
manipulate. The heat guard is of vulcanised fibre. The holder on the right is of a
heavier pattern, and is intended for carbon or graphite electrodes, from | in. up to j in,,
and for currents up to 250 amperes. The heat guard is of metal. Both these holders
are made by the Equipment and Engineering Company, which also supplies a still
heavier holder, designed to take electrodes up to 1 in. in diameter, and to be suitable
for currents of 400 amp^reB.
According to Mr. A. M. Candy, as set out in a paper which be read in November,
MACHINES AND APPARATUS FOB ARC WEU)ING 71
1918, before the Pittsburg Section of the American Inetitute of Electrical Engineers,
the carbon holder, as used in the United States, comprieeB an aluminium rod, one
end of which \b fitted with a connection for attaching the feeder cable, while to the
other end is welded a tube which contains two jaws or clamps for holding the electrode.
The portions of the clamps which are in the tube are tapered, so that when forced into
the tube they grip the electrode firmly. The cable end of the holder is furnished with
an insulating, heat-resisting handle, and a disc shield to protect the operator, not only
from electric shocks but from the heat and light rays emanating from the arc. The
electrode is of solid graphite, usually one inch in diameter and from six to eight inches
long. The holder, which is intended for currents up to 600 amperes, is, Mr. Candy
explains, sufficiently Ught to be handled easily sad is strong mechanically. For
heavier currents a larger holder is necessary. The metal electrode holder as used in
Fig. 60,— Tilling-Stevena Arc Welding Lorry.
the United States — and we repeat here that in that country bare metal electrodes were
much more extensively used, at all events until comparatively recently, than were
covered electrodes, whereas the reverse is the case on this side of the Atlantic — is
considerably Ughter than the carbon holder, and the disc shield is generally omitted
because the heat at the arc is much less intense. The electrode is clamped in the
holder by a earn device, which is so designed as to be capable of accommodating
electrodes of various diameters.
The forms of screens employed for the protection of the eyes and faces of operators
when engi^ed in arc welding are numerous and varied. We illustrated one of them in
an earlier chapter, and we might deal with many more if it were not that no really
useful purpose would be served by doing so. The fact of the matter is that it does not
matter what shape or form they take as long as they afford efficient protection. For
sonje classes of arc welding the necessity for protection is considerably less urgent
than in others. The long carbon arc, for instance, has a much more potent effect on the
surfaces of the human body than have the considerably shorter arcs with which some
72 ELECTRIC WELDING AND WEIJiING APPLIANCES
types of coated metal electrodes operate. Even bo, we have seen caeee in which only
a Bcreen held in. the hand was employed for carbon arc welding, while much more
elaborate precautions are BOmetimes taken by coated electrode welders. It is quite
clear, therefore, that there is no reason why the screens or shields should be of any
particular shape, though it would be as well for factory owners to satisfy themselves
that what is employed will, if properly used, afford the necessary protection.
In this connection there arises the question of the best type of glass to use. It
must be admitted that hitherto this aspect of the matter has been treated by many —
Fio, 51.— Crompton Selt-coDlained Arc Welding Set
though not by all — in a far too haphazard manner. Notable examples to the contrary
were the labours of such investigators as the late Sir William Crookes, who devoted
much careful study to the production of glass which, while affording a good view
of the worki would protect the eyes of workers. I'he problem, however, has not, w©
think, yet reached a definite solution, though several different kinds of " safety "
glasses have been evolved, and many combinations of coloured glasses are in use.
It is comparatively easy to select a combination of colours which will cut off a
very large percentage of the harmful rays, whether of light or heat, and which will at
the same time enable the worker to see what he is doing perfectly well when once
MACHINES AND APPARATUS FOR ARC WELDING 73
the are has been struck. With many such combinations, however, it may be quite
impossible, with ordinary illumination, to see anything at all of the work. Such
a disability cannot be helpful, though we must admit that, when observing the opera-
Fio. ft2.— Crompton Motor Generator Set for Arc Welding.
Fig. 63.— E. and E, Company Elt^trode Holders.
tione of workers using combinations of coloured glasses through which ordinary
daylight could only be faintly seen, we have been struck by the »mall amount of
hindrance it has been.
74 ELECTRIC WELDING AND WELDING APPLIANCES
It has to be remembered that it is not only the visible light rays which have to be
guarded against ; there are also those in the infra-red and ultra-violet ends of the
spectrum. Glass which may cut off those at one end may allow the free passage of
those at the other. It has, however, not been beyond the powers of science to provide
a solution to the problem. Certain glasses having greenish tints have been found to
give excellent results, and it is rather curious that they have not been more extensively
used in this country than has, so far as we are aware, been the case. Glass having
tints of this character and capable of passing a large proportion of the visible rays,
has considerable vogue amongst welders in the United States, especially that made
by the Corning Glass Company, of Corning, New York. Gold-plated glass has also a
remarkable capacity for stopping heat rays, but it is inferior in transparency to other
glasses.
The following summary of the effective means for eye protection against the
various harmful radiations that are particularly 'associated with welding operation,
forms the conclusion of an article recently written on the subject by Mr. W. S. Andrews,
of the Consulting Engineering Department of the General Electric Company of America,
and wiU doubtless be read with interest. It appeared in the December, 1918, number of
that company's Review, from which we have already quoted in preceding chapters : —
(1) ''The intense glare and flickering of the visible rays should be softened and
toned down by suitably coloured glasses, selected by an expert and having a depth of
colouration which shows the clearest, definition combined with sufficient obscurcUion of
glare, which last feature can be best determined by the individual operator.
(2) '* When infra-red rajrs are present to a dangerous degree, a tested heat-absorbing
or heat-reflecting glass should be employed, either in combination with a suitable
dark-coloured glass, when glaring visible light is present, or by itself in cases where
the visible rays are not injuriously intense.
(3) " In guarding the eye from the dangerous ultra-violet rays, it must be care-
fully noted that ' pebble ' lenses are made from clear quartz or natural rock crystal,
and this material being transparent to these rays offers no protection against their
harmful features. On the other hand, ordinary clear glass is a protection against
these rays when they are not very intense, but dark amber or dark amber-green glasses
are absolutely protective. Glasses showing blue or violet tints should be avoided,
excepting in certain combinations wherein they may be used to obscure other colours."
CHAPTER. XI
•RESISTANCE WELDERS OP THE ELECTRIC WELDING
COMPANY, LIMITED
Among the pioneers in the use of the Thomson system of electric resistanxje welding
in this country was the Electric Welding Company, Limited, of 2S Basinghali Street,
London, E.C. It has consequently bad a considerable amount of experience in the
design and construction of machines working on this principle, and the result of that
experience has been that it has arrived at the conclusion that it is wise to make
electric welding machines amply strong, since the users of such machines are very apt
to demand from them very considerably more than their rated capacity. Hence one
of the distinguishing features of the machines which the company builds is robust
construction, and since the machines are also characterised by good mechanical and
electrical design a ghort reference to s'>me typical examples will doubtless be of
interest. It so happens that just recently the company has introduced several new
types of electric butt welders, and to them we propose to refer in what follows. It
must not, however, be thought that it only constructs machines of that type, for it
also makes spot welders, seam welders, wire welders, chain welders, and machines for
many other purposes, aU of which it would be manifestly impossible to discuss.
The machine illustrated in Fig. 54 is intended for butt-welding heavy steel tubes
up to 3| in. in diameter. It will be observed that the electrode clamps for gripping the
pipes are of the horizontal type with top opening so that the pipes to be welded may
be dropped in from above. This construction is advantageous when the work is of a
heavy character, or when the tube being dealt with is in the form of a close spiral as,
for example, in the case of the coils for a refrigerating machine. The adjustment
between the clamps to suit various diameters of pipes is obtained by means of the two
hand wheels at the back of the machine which adjust the position of the rear clamps.
Each of the forward or working clamps is furnished with a hand-operated cam lever
by which the work is firmly gripped by one movement. The clamping blocks and the
platens on which they move are cooled by water circulation.
Heavy work such as the welding of pipes as large as 3| in. in diameter requires a
considerable pressure properly to consolidate the weld, and in the machine under
consideration it is applied by means of a 12-ton hydraulic jack which is operated by
a lever.
The machine, working as it does on the Thomson principle, embodies a static
transformer, and the primary winding is provided with five tappings controUed by a
selector switch for adjusting the voltage, and hence also the current in the secondary,
winding, to suit the various sizes of tube, etc., dealt with, the smallest tube which the
machine is designed to weld being 1^ in. in diameter. The main control switch, which
is oil immersed and enclosed in a galvanised steel tank, is operated by the foot lever
and wire rope, which may be seen at the front of the machine at the left-hand side.
Machines of this type, some of which are, we understand, being used by some of the
largest tube makers in this country, are also suited for the welding of straight rods and
Fig. 64.— Electric Welding Co.-Butt Welder for Tubes, Rode, etc
Fw. 65.— Electric Welding Co.-Biill Wel,i«r with Radial Weldin
KESISTANCE WEU)ERS OF THE ELECTRIC WELDING CO., LTD. -77
bare, angles, corner welds in rectangular frames, and other forma of work in effecting
which it IB convenient to insert the parts to be welded from the top.
tfts" A machine similar to the foregoing in size, but differing from it in the fact that the
clamps are of the horizontaLoblic|ue type, is shown in Fig. 55. In it the welding blocks
are arranged in radial fashion, and are operated by screws and hand wheels. Tlus
form of clamp is especially suitable for the welding of rings, tyres and other endless
shapes of work, and the particular machine illustrated is designed to deal with cross-
sectional areas up to six square inches. Adjustable springs are provided so that the
applied pressure may not exceed a predetermined amount.
Fio. 56. — Electric Welding Co.— Butt Welder for Miacellaneous Repair Work.
A welder specially designed for miscellaneous repair work, which has been adopted
by several British railway companies for renewing the iron work of rolUng stock, is
shown in Fig. 66. The four clamps, or jaws, are set at an angle and are adjustable by
hand wheels. Each has its own water circulation system. The pressure is appUed, as
in the case of the first two machines, by means of a hydrauUc cyhnder. This type of
machine has proved very serviceable in many kinds of railway material repair work.
For example, the truM rods, brake rods, draw-bar rods, and similar parts of the
underframing of coaches, are frequently found to be corroded and worn, while the
forgings at their ends may still be in good condition. By cutting away the worn rods
and welding on new ones the cost of new forgings is saved, and the resulting economy
is found to be quite considerable.
A machine of considerably different type is shown in Fig. 67. It is a hand-operated
welder specially designed for light work on steel strips, small rings, perambulator tyres,
78 ELECTRIC IWELDING AND WELDING APPLIANCES
cycle parts and such-like small articles. In the illustration the casing of the lower
part has been removed in order to show the construction of the transformer. The
secondary winding consists of laminated copper strip, which encloses the primary coil
and embraces one limb of a rectangular iron core. The endd of the secondary winding
are bolted to fixed platens which carry the clamps and pressure device. The elsimps,
which are of the vertical type, are operated by cam levers, and are so arranged as to
enable the work to be inserted from the front, and to be gripped by a single movement
of the cam lever. The pressure device consists of a toggle and lever, and there is an
automatic switch, which, however, is not shown in the engraving, by means of which
the primary current can be cut off as soon as the sliding clamp reaches an adjustable
stop. This machine is, we are informed, capable of welding steel strip as thin as
No. 22 S.W.G., two inches wide, with uniform and reliable results when operated
by a lad.
An entirely automatic welder is shown in Fig. 68. It is intended for welding hoops,
rectangular frames, buckles and rings at a speed which may amount to as manj'^ as
600 welds per hour. The transformer and the electric parts of the machine are of
standard type, but the clamps are mechanicaUy operated by a system of cams from
a main shaft which is driven by a clutch pulley controlled by a treadle attached
by chain to the rod suspended from the pulley at the right-hand side of the machine.
The machine is belt-driven, and as soon as it is started up the right-hand platen moves
away from the left, with the result that the space between the arms of the clamping
device is increased and the clamping jaws raised. As soon as this occurs the operator
puts the pieces to be welded on the electrodes, so that they abut against each other
evenly with the joint in the centre. The clamping jaws then descend and securely
hold the pieces in place. The primary switch then closes and the current flows.
As the metal softens the pressure of a spring causes the right-hand platen to move
towards the left, with the result that the metal is upset at the points, and the weld
made. The steel clamping jaws are then raised, the right-hand clamp then again
moves away from its fellow, the operator removes the welded piece, and the cycle of
operations is again repeated.
This machine is of 6 kilowatts capacity, and is intended for welding stock up to
I square inch cross section, at the rate, as already said, of 600 welds per hour, the
actual time required for heating each weld being, we gather, about three seconds. In
both this machine and in that shown in Fig. 57 there is a circulating water-cooling
system.
SoMB Large American Spot Welders
Some exceptionally large resistance welding machines, which give some idea of the
far-reaching possibilities of this method of welding, have recently been constructed
by the General Electric Company of America. First of all a fixed experimental
machine was built which had a welding current capacity of no less than 100,000
amperes, and a pressure capacity of 76,000 lb. As a matter of fact the maximum
current and pressure at which the machine had been used up to the time at which
the memorandum from which we are obtaining our information, and which appeared
in the issue for December, 1918, of the General Electric Review, was written, were 72,000
amperes and 30,000 lb. respectively. With them three thicknesses of 1 in. plate had
been spot welded. Working on the data obtained with that machine the company
set about the designing of special portable appliances for use in the fabrication of
structural parts, particularly intended for ship work. An investigation of the subject
showed that four-fifths of the work of this character could be carried out by a machine
s
I
■5
i
I
u
I
so ELECTRIC WELDING AND WELDING APPUANCES
having a reach of 12 in., and that a machine with a reach of 27 in. would include the
other fifth. Since it was calculated that both the weight of the machine and the
kilovolt-amperes required for its operation would be about 33 per cent, greater for
the 27 in. reach machine than for that having the 12 in. reach, it was decided to build
two machines only that with the longer reach. The standard pneiunatic
riveter w&a U lei, w far as the general construction of the machines was
concerned, th pressure being applied by means of an air cylinder and a
lever system. ilso provided so that the machines could be picked up by a
crane and hel where required. An engraving showing the larger of the
two machines ;. 59, which is reproduced from the Review mentioned above.
The maxi: ; current available in these^ machines, n-ith a steel plate
enclosed to tl; f the gap, is about 37,&00 amperes. I'he current applied to
the primary winding had a periodicity of 60 and a volti^e of 534. Reduced voltages
to give pmaller currents in six progressive steps
— the lowest being 267 volts — were furnished by
means of separate regulating transformers. This
. arrangement was provided to meet the possible
requirements for a considerable range of thickness
of work, as well as for experimental purposes. As
a matter of fact, however, it was subsequently
ascertained that the machines would operate satis-
factorily, on work of thicknesses extending over
the range on which they are likely to be used, when
connected directly to a 440-volt, 60-cycIe current
with no regulating transformers. Two plates are
with these machines welded togetherin spots from
1 in. to Ij in. in diameter in from twelve to fifteen
seconds. Thicker plates, of course, require more
T«.._„.. , ^ time, and thinner plates less time.
Ft<i. 09. The welding current under these conditions is
American Spot Welder tor Ship Work. about 31,000 amperes, the corresponding primary
current for the 12 in. mRchinc being fibout 600
amperes, and for the 27 in. machine about 800 amperes, the voltage in each case
being 440. The expenditure of energy was therefore 264 and 352 kilovolt-amperes
in the two machines respectively. The secondarj- voltages with these iigures work
out at about 8 J for the smaller machine and 11 J for the larger.
The maximum mechanical pressure for which ther.e machines were designed is
25,000 lb. It is obtained by means of an 8 in. cylinder working with air at 1001b.
per square inch pressure, and a lever arm with a ratio of 5 to 1. Alteration in the
pressure apphed is obtained by varying the air pressure, a reducing valve being
provided fo,r the purpose. A gauge pressure of 70 lb., giving a pressure on the work of
17,500 lb., has been found to give good results with J in. plates.
The conductor for the primary windings of these transformers m | in. by ^ in.
annealed copper tubing, insulated with asbestos tape, wound directly on an insulated
core, alternate layers of sheet asbestos and mica pads being used between layers of the
primary winding, between primary and secondary, and between primary and the core.
There are four layers of thirteen turns each in the 12 in. machine, and three layers of
thirteen turns each in the 27 in. machine. The U-shaped single-turn secondaries,
which were slipped over the outside of the primary windings, were constructed of two
copper plates, each | in. thick and 6| in. wide, assembled one inside the other, J in.
SOME LARGE AMERICAN "SPOT" WELDERS 81
apart. Xarrow Btrips of copper were inserted between the plates along the edges, and
were brazed in poeition bo as to make a water-tight passage for the circutatioa of the
cooling water. At 31,000 amperes the current densities in the secondaries ia about
6200 amperes per square inch, the corresponding densities in the primary windings
being about 7000 amperes per square inch in the 1 2 in. machine and 9000 in the 27 in.
machine.
Spacing blocks of a compound of asbestos and Portland cement were used at the
onds of the core and at the ends of the winding layers, and the complete transformer,
after assembly, was impregnated with " bakelite." The result, we gather, was a .
solid mechanical unit which is not injured by heat as long as 150 deg. Cent, is not
exceeded. Several welds can, we are informed, be made without turning on the cooling
water before that temperature is reached. The cooling water wag given two paths,
one being through the primary winding, and the other through the secondaries and
the electrodes in Series.
When it was found that these machines worked satisfactorily it was decided to go
Fio, 00. — Lai^ American Duplex Spot .Welder.
a step further, and to build a larger machine, intended specially for the application
of electric welding as a substitute for riveting on parts of ships hulls composed of
large-sized plates, which may be "fabricated " before they are assembled in the
ship. It was decided to give the machine a 6 ft. gap, and to make it capable of welding
together two plates } in. thick in two spots at the same time. It was realised that
it would be useless to attempt to make the machine even semi-portable and the form
it was given is shown in Fig, 60. With the welding circuit enclosing a 6 ft. gap, and
carrying the very heavy current necessary to weld | in, plates, the kilovolt-ampdrage
would have been very high. It was proposed, therefore, as a means of greatly reducing
the energy consumption, and at the same time of doubling the amount of work turned
out, to use two transformers with two sets of electrodes, and to arrange them as shown
diagrammatically in Fig, 61. By this arrangement it was made possible to weld two
spots at the same time. The transformers are mount«d in the frame of the machine
as neai- to the welding electrodes as possible, so as to obtain the minimum reactance
in the welding circuit. The polarity of the electrodes on one side of the work was made
the reverse of that on the opposed electrodes, thus giving a series aiTai^ement of the
transformer secondaries, the pathway of the current being indicated by the dotted
82
ELECTRIC WELDING AND WELDING APPUAXCES
Winding
hsMsH, It will be gathered that the cmrent from each tmisform«' Oaws through both
of the KpotM being welded. The bottom eleetrodee are j^tatiooaiT, while the top elec>
trode*$ are capable of independent vertical motion, so as to engage the work. Previous
teiftn with the original experimental machine had shown that soceessfoDy to weld
two KpotK at the iiame time with such an arrangement as we have described, it was
ntcei^hary that the pressure should be indepoidently applied. Otherwiae, because of
inequalities in the thieknetss of the work, or because of wear and tear of the dectrodes,
the preM»ure might be mu ?h greater on one of the spoti> than on the otlier, which would
naturally result in unequal heating, since the resistance to the flow of the electric
current and the consequent heating effect are less on the spot with the greater pressure.
The two top electrodes were therefore mounted on separate plungers operated by
separate pistons through independent levers.
The pressures obtained in this duplex machine with an air pressure of 100 lb. per
square inch are 30,000 lb. on each spot,
or a total pressure of 60,000 lb. on the
work. The two air cvlinders are
mounted on a cast iron bfed-plate in
the back part of the machine. The
levers connecting the pistons to the
electrode plungers, which are 7 ft. in
length, were made of cast steel in order
to obtain the necessary strength.
The maximum welding current for
which this enormous machine was de-
signed is 50,000 amperes, this secondary
current being obtained with 60 -cycle
current at a voltage of 500 applied to
the primary winding. With this current
in the secondaries the current in the
primary windings was 1800. The
primaries of the two transformers are
arranged in series and the kilovolt-
ampdrage in each transformer is 450,
or a total of 900 kilovolt-amperes. The
current densities in the primaries and
the secondaries of these transformers
was no less than 9000 and 7000 amperes
per square inch respectively. The winding consisted of two layers of fourteen turns
each for each of the primaries, and a single turn for each of the secondaries, one
layer for the primary being arranged inside and the other outside the single turn
secondary winding. ThcHe tranrformers, which, exclusive of terminals, only measure
11 in. by 16 in. by 18 in. over all, are thought to be the smallest ever built for so
large a rating.
It can bo well understood that when dealing with such heavy currents the question
of the electrodes becomes of great importance. In the portable machines described
above the current density in them is given as being about 60,000 ampdres per square
inch. It has to be remembered, too, that when heated by the passage of this current
the tips of the electrodes are subjected to a pressure which may amount to as much
as from 16,000 lb. to 20,000 lb. per square inch, and that copper— the best available
material for the purpose— softens at a temperature considerably below the welding
To tmrmltml
of primary
winding
of uppm
tnuiBjormot
Flo. 61.
Electrical Arrangementfl of Duplex Welder.
SOME LARGE AMERICAN " SPOT " WELDERS
83
temperature of steel. The electrodes, which have tips in the form of very flat truncated
coned, are given such shape as is calculated to afford as free conduction as possible of
the current to, and of the heat away from, their tips. Moreover, they are adjacent
to large masses of metal of high electrical and heat conductivity, and their bodies are
internaUy water-cooled by a stream of water flowing continually through. Still, in
spite of every precaution, which included the clearing away by meaniS of a sand blast
of rust and scale from the stirfaces of the plates at the points of impingement of the
electrodes, deformation of the tips of the electrode occurred, thus increasing the area
of contact with the work and reducing both the current and the pressure densities
below the values needed for welding. To overcome this difficulty thin copper caps —
^^ in. thick — ^fitting over the tips of the electrodes have been tried, and as many as
160 welds have been made with a single cap before it required to be renewed. Another
method tried was to have renewable tips to the electrodes, and it has been proposed
to employ electrodes which combine the features of the removable tip and the cap,
but the last-named had not been tried at the date of the Review to which we are
referring.
As far as we are aware, the machines described in the foregoing are the largest
and most powerful which have, up to now, been constructed.
CHAPTER XII
OIL-DRUM-MAKING BY RESISTANCE WELDING
In an earlier chapter we mentioned that the Steel Barrel Company, Limited, of Ux-
bridge, in addition to its extensive use of the carbon arc, also employed the resistance
welding process. It does so for the production of sheet-steel drums such as are used
for containing petrol, petroleum and other such oils and liquids, and it finds it most
satisfactory for the purpose. We ourselves have seen a five-gallon drum made by this
method at Uxbridge which, when filled with petrol, and weighing in all about 49 lb.,
had undergone the drastic test of being dropped no less than seven times from different
heights — nearly 20 ft. was, we believe, the highest — and it did not show the least
sign of leakage, though it was severely battered about and distorted. We hiyve on
several occasions watched the various processes of the manufacture of these drums
and we shall now proceed to describe them.
It may be explained at the commencement that some years before the outbreak of
hostilities, Mr. T. T. Heaton, the general manager of the company, when on a visit to
Germany saw in operation a series of machines which he thought could be adapted to
perform the kind of work which he had in view. A set of machines was, therefore, ordered
and eventually delivered. As originally built, however, they failed to do what was
required of them, and had to be considerably modified, with the result that in their
present forms they certainly operate extremely well, and with great speed. The size
of drum which we have seen made was that intended to hold five gallons, but the same
machines are equally well fitted for making larger or smaller vessels, the largest or
smallest for which they are suited being, we understand, 2 and 15 gallons respectively.
For making the drums four distinct types of machines are employed, and one type is
represented by two slightly different machines, so that it may be said for the welding
alone five different machines are required. We shall refer to them in the order in which
they are used.
The drums are made of mild sheet steel of Nos. 24 to 18 B.G. thickness. The
sheets are first of all cut to correct size, and accurately squared. They are then curved
into cylinders, by passing them through rolls in the usual manner, the pressure being
so adjusted that only one passage through the rolls is necessary in order to obtain
the desired curvature. To obtain really satisfactory welds by the processes employed
it is necessary that the sheets should not only be free from scale and rust, but that
aU oil, grease and dirt should be removed from their surfaced. To effect this the
cylinders, when rolled, are immersed for a short time in a bath containing a mixture of
acids diluted with water. When they have remained for a sufficient time in the bath
they are taken out, washed in several changes of water and dried. In this connection
we may mention that, as the washing water has, after use, to be discharged into a
canal which passes by the works, its acid contents have to be neiitraUsed. To do this
it is passed through a channel which is charged from time to time with the spent
material — calcium hydrate — taken from the acetylene generators. We understand
that this employment of an otherwise useless waste product has given quite satisfactory
results.
OIL-DRUM-MAKING BY RESISTANCE WELDING 85
The cleaned and dried cylinders are then ready for the welding prooes^s, the firBt
of which is to give the necessary overlap to the edges of the longitudinal seam^ and
to secure these edges in the correct position for the welding of the seam. The machine
employed for the purpose is a pedal-worked spot welder, the lower electrode of which
is fixed, while the upper is reciprocated vertically by the pedal. The machine is mani-
pulated by two boySj one of whom only assists in holding the cylinder in the required
position. The correct overlap is obtained by causing the longitudinal edges of the
rolled cylinder to enter two slots arranged one on one side, and the other on the other
of a horizontal bar, the two slots being at slightly different levels, and being given
such depths that when the edges of the curved cylinder plates are pressed as far as
they can go into them by the two boys, one pressing on one side and one on the other,
the exactly correct overlap for the joint is obtained. The machine operator then,
after making certain that the ends of the two edges, which, we may explain, are aUowed
to project some little way from the end of the slotted rod so that they can be readily
pressed together, coincide, or, in other words, that the circumferential edge lies in
one plane, adjusts the extreme end of the seam immediately beneath the vertical
electrode of the machine and presses the pedal. The result is the formation of a minute
spot weld, which effectually holds the two edges together with the correct overlap.
The amount of overlap being given when we saw the machines at work was about
three-eighths of an inch, and the diameter of the spot weld about one-eighth of an
inch. Still keeping the edges of the cylinder in the slots in the bar, the cylinder is
moved horizontally for a short distance, and another spot weld made. This process
is repeated several times, until only the length of seam at the end remote from the
first spot weld remains. The cyUnder is then removed from the machine, the unsecured
end of the seam is adjusted in position on the lower electrode, and the upper electrode
brought down by the pedal so as to make the final spot weld. The whole process,
which may from the description appear to take a long time, is actually carried out in
a few seconds, and results in the formation of an accurate cylinder, the edges of the
longitudinal seam of which are held securely in place for the next operation, which
is that of welding the seam.
For the welding of the seam the cylinder is placed in the horizontally reciprocating
frame of a machine, which is furnished with revolving wheel electrodes arranged,
vertically, one above the other. When in position in the frame with the seam of the
cylinder coming immediately between the two wheels, the movement of a horizontal
. lever causes the top wheel to be moved downwards, so that the seam is pressed between
the two wheels, while simultaneously the horizontal frame, and with it the cylinder,
is made to move slowly in such a way that the wheels, or rollers, as they revolve with
the seam between them follow the latter accurately and weld the two edges securely
together. As in the case of the fir^t machine the whole length of seam is not welded
from one end. The welding of the seam is begun three or four inches from one end,
and the weld taken from that point to the further end of the seam. The cylinder is
then taken out of the frame, reversed, and put into the frame again. The remainder
of the seam is then welded in the same manner. The whole process, including the
reversmg of the cylinder, takes only about ten seconds. By reason of the fact that the
cylinder is held in and moves with the frame, the weld is in an exactly straight line
and looks extremely neat and busine^sUke.
The next process is the fitting and welding in of the top end of the drum, that is
to say, that end which carries the bunghole. The ends, whether that at the top or that
at the bottom, are formed of circular steel plates of Nos. 24 to 18 B.G. thickness,
dished so as to have a rim standing up at right angles to a depth of about 1 in. The
86 ELECTRIC WEIJ)ING AND WELDING APPLIANCES
ends when dished are of such a size that they are an easy driving fit into the end of the
cylinder. The hole to take the bung ring is, of course, punched before the end is
fitted into the cylinder. After the end has been placed in position, an operation which
is effected simply by pushing, or, if necessary, light tapping, the operator satisfies
himself that it is neither too far in or too far out, and then places the cylinder horizon-
tally on a frame in a welding machine, the arrangement being such that the cylinder
can revolve on its axis. The welding machine is of the wheel tj^e, the two wheels
being placed vertically one above the other. The top wheel is revolved by power,
while the lower wheel is free to revolve on its spindle. All being in readiness the
machine attendant depresses a lever which raises the bottom wheel so that the rim
of the cylinder end is gripped between the two wheels, and welding commences. As
the upper wheel is revolved mechanically the drum cylinder is revolved with it, and
gradually the whole seam is welded right round its periphery. . All that the attendant
has to do is to see that the rim is kept continually between the two wheels, this being
done by guidance with the hand, which ensures that the end of the cylinder revolves
in one plane. This operation, like those which have gone before it, is also effected in
but a few seconds of time.
The next operation is the welding on of the bung socket, or boss, which may be of
two types, i.e. that for use with a cork bung, and that for a screw plug. In both cases
the welding process is the same. The cylinder is threaded over an upright, the top of
which is provided with a spindle which fits into the hole punched in the end piece,
and is provided with a shoulder on which the metal of the end piece can rest, and
which forms the lower electrode and the anvil for the welding operation. With this
arrangement, as will be understood, the cylinder can be revolved vertically round the
bung hole as a centre. When the cylinder is in position the bung socket is threaded
over the projecting top of the spindle above mentioned, and the machine put in motion.
The effect is to cause an upper electrode to be mechanically reciprocated vertically
up and down, and at the lowest point of each stroke to press the metal of the cyhnder
top and the flange of the bung socket together, and form a spot weld. Between each
stroke of the machine the cylinder is revolved through a small angle, the effect being
that a series of spot welds, which just overlap one another, is formed all round the
periphery of the flange of the bung ring, and when the cylinder has been revolved
through a full circle the welding is completed. The result is neat and satisfactory in
every way, and the whole operation is very quickly effected.
Next comes the welding on of the handle, which is simply a strip of sheet steel
bent through four right angles in the following manner ^l l^. The
machine used for the welding is of a similar type to that used for welding in the bung
socket, but of a slightly different construction. There is, however, a vertical lower
electrode which also acts as an anvil, and a power-worked vertically reciprocating
upper electrode. The handle is placed in position and some five spot welds quickly
made on each of its ends where they come in contact with the metal of the drum top.
These welds, though they look quite small, are sufficient to weld on the handle so
securely that a very considerable pull would be required to tear the handle from the
drum top.
Finally, as far as the welding processes are concerned, the bottom piece, which
exactly resembles the top piece, saving that it has no bung hole, is fitted in and welded
in place, the machine employed being identical with that used for welding in the tops.
The finished drum is then taken to a grindstone, by means of which the rough
edges of the ends are smoothed, and it is then ready for testing and painting. Testing
is effected by inserting a closely fitting nozzle into the bung hole, applying internal
OIL-DRUM-MAKING BY RESISTANCE T^^LDING 87
air pressure, and plunging the drum in water. Out of a large number which we saw
teg^ted we saw no sign of air leakage. Drums of this tjrpe are turned out in large
numbers and with wonderful rapidity. There is not, we should say, a single one of
the welding operations which takes a quarter of a minute, the shipping and unshipping
of the cylinder in the machine being included in that period.
Having described the welding processes, we can say a few words regarding the
machines. They all, of course, work with alternating current. The company does
not generate alternating current nor does it convert its own direct current into alterna-
ing. It ^o happens that a supply from a local company is available. The voltage
at which it is received on the works is 2800, and the periodicity is 60. Near the point
at which the current enters the works the pressure is transformed down to 220 volts,
at which pressure it is distributed to the resistance welding machines. The secondary
voltage of the latter, that is to say the difference of potential between the elegtrodes
applied to the work, is very low. In no case id it, we understand, more than 1 volt, and
in one machine, at any rate, it is as low as half a volt. In this, connection it has to be
remembered, of course,, that the material being dealt with is very Ught, only Nos. 24
to 18 B.G.
Of the machine used for spot welding the longitudinal seams there is not much
to say beyond that which has already been said. The motion involved is simply the
reciprocation of the upper electrode, which lA effected by pedal against a spring. Just
after the final pressure is put on, the current in the primary circuit is automatically
cut off. Both upper and lower electrodes are cooled by water circulation.
The longitudinal seam weldmg machine, on the contrary, has many points of
interest. Its two electrode wheels, the spindles of which are carried in bearings, are
mounted at the ends of two long arms which form the two terminals of the secondary
of the transformer. They are both of them free to revolve and are cooled by a large
portion of their surfaces being in rubbing contact with cheeks which are provided
with a water circulation system. Rubbing contact is depended upon for the conduc-
tion of electric current. The mechanical arrangements are worthy of special mention.
It will be remembered that the movement of a horizontal lever both brings the elec-
trode wheels nearer together so* that they press on both sides of the work, and also
puts the cylinder-carrying frame in motion. The action is, briefly, as follows : The
upper arm, which carries the upper electrode wheel, is hinged near its rear end, that
is the end away from the wheel, and the rear end itself is pin-connected to a system
of levers which are actuated by the horizontal lever. The motion of the latter im-
parts just sufficient motion to the arm carrying the wheel to enable the latter to bear
with the desired pressure on the work. Connected to the horizontal lever is also
the actuating member of a clutch which can put a train of revolving gearing into and
out of mesh with a toothed wheel on a shaft carrying a pinion which is in mesh with a
toothed rack attached to the horizontally reciprocating frame which carricEl the
cylinder. There is an arrangement by which the frame when it has completed its
forward movement is quickly returned to its starting-point. The power to work this
machine, and the others that require it, is obtained by belting from a countershaft.
It will be understood that in this case the current is kept on during the whole of the
welding operation, and that as the cylinder is forced between them the electrode wheels
revolve so that no one point in their peripheries is kept long in contact with the heated
metal which is being welded. The weld is continuously being consolidated by the
pressure between the electrode wheels.
The top and end welding machine is, like that which has just been described,
exceedingly ingenious. The upper wheel, as we have said, is kept continually revolving,
88 ELECTRIC WELDING AND WELDING APPLIANCES
the lower wheel being free on its shaft. The latter, of course, revolves when work is
being done. The lower carriage wheel is capable of vertical motion by means of a
system of levers which produce a certain pressure on the work when it is gripped
between the wheels. In order, however, to allow for irregularities in the thickness
of the material passed between the wheels, as, for example, the overlap of the longi-
tudinal joint, the carriage of the lower wheel is furnished with a strong coiled spring
which allows of just sufficient '* give " to prevent injury to the machine or undue
pressure on the work. In this machine also the current is kept on during the whole
period of welding. Cooling of the electrode wheels is effected in a manner very similar
to that employed for the longitudinal seam machine. The electrode wheels in both
machines are of pure copper. It has been found impracticable to employ an alloyed
material, since the alloy is eventually volatilised leaving the copper in a spongy state.
During use the contact surfaces of the wheels become coated with a more or less non-
conducting surface, formed, possibly, by oxide from the steel plates. This is removed
at intervals by light scraping. After continuous work for perhaps a fortnight, the
wheels may get slightly out of shape. If this be the case they are removed from the
machine and a very light cut taken from the peripheries in a lathe.
The reciprocating spot welding machines employed for affixing the bung socket
and handle do not call for any extensive description. The reciprocating motion is
mechanically operated, the upper electrode in the case of the former machine making
strokes at the rate of about one per second, or even less, which appears to give ample
time for the operator to revolve the drum through the requisite angle between each
stroke. Each and all the machines work smoothly and well, and produce excellent
results. ' Taken altogether the whole system turns out drums of first-rate quality
in a wonderfully expeditious manner.
CHAPTER XIII
RESISTANCE WELDERS OF THE Al MANUFACTURING COMPANY
A FIRM which, though it has not been in existence for many years, has nevertheless
developed some excellent welding machines of various types is the A 1 Manufacturing
Company, of Industry Works, Sunbridge Road, Bradford. It confines its activities
entirely to resistance welding and to the production of machines and accessories for
welding on that principle. It contends, and with some show of right, that resistance
welding and its possibilities have been to a large extent outshone and overlooked by
reason of the extensive publicity which has recently been given to arc and acetylene
welding. It points out that neither of the two latter processes lends itself to any-
thing like the same extent to repetition work as does resistance welding, and further,
that whereas both of them require a no inconsiderable degree of skill for the production
of good Eiound welds, there are many directions in which quite unskilled labour can
achieve excellent results with resistance welders without the necessity for any special
training. The comfnent we would make concerning these contentions is that it was
largely with the idea of correcting wrong impressions regarding electric welding as
a whole that the publication of this series of articles was undertaken. Electric welding
in various branches has been practised for a number of years now, but it must be ad-
mitted that the multifarious nature of its applications has not, until comparatively
recently, been recognised by the large majority of our manufacturers. There is little
doubt, however, that the future will see its adoption far more extended than it is even
now, and it will be found that there will be ample scope for both the resistance and
arc systems ; for each will be discovered spheres in which it operates with best effect.
This by the way.
Let us now turn to the firm's machines. We have before us a list which shows that
it has evolved as standard patterns eight spot welders numbered to 7, three seam
welders, Nos. S3, S4 and S5 ; and eight butt welders, numbered BOO to B8. The
rated continuous working capacities of the spot welders vary from -j-^ in, added thick-
ness in the smallest mp«chine to | in. added thickness in the largest machine, the
material dealt with being mild steel and iron. For intermittent working the thick-
nesses may be increased to 3^ in. and J in. respectively. *' Added thickness," it need
hardly be explained, is the total thickness of the pieces of metal that are to be welded
together. The six smaller machines are also stated to be capable of welding brass and
aluminium, the thicknesses dealt with var3dng from ^^ in. with machine No. to ^^ in.
with machine No. 5. The smallest seam welder is designed to take 3% in. added thick-
ness, and the largest ^ in. with mild steel or iron, the thicknesses with brass being
just half those figures. The diameter of material which the smallest butt welder —
No. Boo — is intended to take is ^^ in., while the largest machine — B8 — is designed
to operate with material up to 2^ in. in diameter, or, say, 5 square inches in cross
section — the figures given relating to ferrous metals. Copper and brass can be welded
in the five smaller machines, the diameters varying from .02 to .0625 in the smallest
machine to | in. for copper and | in. for brass in machine No. B5. In addition to the
foregoing, there are four sizes of seam welding attachments and three butt welding
■90
ELECTRIC WELDIXG AND WEIJJING APPLIANCES
attachments which can be applied to different sizen of the finn's spot welders, so that
the latter can be temporarily converted for the purpoxes named. The four eeatm
welding attachments can deal with added thicknesBes of -^^ in., ^ in., ^ in. and ^\ in.
respectively, while the three butt welding attachments can take diameters of from
^ in. up to ^ in., | in. and J in. respectively, the sizes given referring to mild steel or
iron in each case.
The foregoing are standard machines and appliances, but they do not by any me&ns
constitute the whole of the firm's output, for a not inconsiderable proportion of its
business consists in the design and manu-
facture of machines specially worked
out and constructed to meet the peculiar
requirements of clients.
In principle, of course, the "A I"
machines are identical with other resist-
ance welderH. They a31 work with
alternating current, and each contains
a static transformer, the primary wind-
ing of which has many turns, while the
secondary, in general, consists of one
or two turns only. It is in their details
that these machines are differentiated
from the products of other makers.
As typical of the company's spot
welders, we give in Fig. 62 a view of
what is known as the No. 2 spot welder.
It is a machine which is specially in-
tended for the production of hollow-
ware and general light work with iron
or mild steel \ip to J in. added thickness
for continuouR working, and up to ^ in.
added thickness occasionally. As a
maximum it requires 6 kilowatts of
energy to operate it. The standard
clearance of the stakes or arms — that is
to say, the distance clear from the
electrodes to the back of the arms, is
9 in., and the top arm is so designed
that it can be extended to 16 in. in
length as required. With arms of
standard length the net weight of the
machine is 462 lb. Stakes of greater length, so as to give clearances of 18 in., 24 in.,
or 36 in., can, hoM'ever, be fitted if required, and the weight with the longest stakes
becomes 501 lb. The top arm or stake is hinged at the same level as the top of the
lower electrode, with the object of ensuring a straight pressure on the weld and none of
the current passes through the hinge, so that the latter docs not become heated. The
top and the bottom arms are both fitted into round socketM, so as to allow them to be
twisted to the right or to the left, so that awkward positions of the weU may be reached ,
while the lower electrode can also be moved up and down in the slots formed in its
carrier and the latter can, itself, be moved from side to side. In the standard machine
the top arm is solid, and the electrode it carries is water-cooled, as is also the lower
Fio. 62.— "A I" Siwt Welder.
RESISTANCE WELDERS OP THE A 1 MANUFACTURING COMPANY 91
electrode. The upper electrode, as will be observed in the engraving, is of considerable
length, so as to allow of a long range of adjustment of the lower electrode arm. The
upper electrode is pierced at its lower end with a hole drilled to a Morse taper so as to
take the shank of a tip piece, which can hence be replaced when it is worn or deformed.
The lower electrode tips are also renewable, but the tips are screwed in and not tapered.
The renewable tips are conical in shape, and
are made flat at the extreme tip. It will be
noticed that the hinged upper electrode arm
is fitted with an adjustable balance weight,
BO that different lengths of overhang of the
arm can be allowed for. By it the force
necessary to operate the machine may be
reduced to a minioium.
It is said that on small articles of, say,
30 B.W.G. mild steel, that can be quickly
handled, from 40 to 50 welds per minute
can easily be made with this machine. The
standard winding is for 50-period single-
phase alternating current at 200 volts, but,
of course, other windings can be supplied if
required, though for them we understand
that an additional charge is made. The
slotted box seen at the side of the machine
is a change-over switch by which nine
separate tappings on the primary winding,
whichwill give nine strengths of current.may
be obtained in the secondary winding. The
speed of working can -therefore be varied
over B. wide range. No. 1 is the fastest and
No. 9 the slowest, and there is an " off "
position by means of which the winding is
cut right out of circuit. In some of the
firm's machines this switch is replaced by
a series of plugs, there being a fast (F) plug
and a slow (S) plug and tour further plugs
available for use with either the S or the F
plugs, the combination giving eight working
speeds. A thimble is provided on the
pedestal into which can be sweated an
earthing uii'e, so as to remove the possibility
of the operator receiving a shock should
the frame of the machine accidentally be
made " live." P,^,^ 63.-" Al " Automatic Sttitcli.
The machine is worked by pedal, which
can be swivelled so as to be arranged in the position most comfortable for the operator,
and this pedal actuates a vertical rod fitted at the rear of the machine. The top of
the rod passes through a hole in the end of the upper electrode rocking arm.
The upper part of the rod is threaded through a spring, which, when the pedal is
operated, is compressed and causes the upper electrode to be pressed down on to the
work and eventually to consolidate the weld. The initial compression of the spring can
^ ELEf^Rir WELDIXO AXD WELDIXG APPLIAXCK
^^ r^/jkUtd t>T ■:«aci'« of a c-^t. «o ai^ to ^-'^v f^.r ?h^ dif «VK:t pffV!<««rM required when
w^ifiinf iiHltrttA tfcir^krj^^*^^^ of mtrtiL TLene- i« a f^^riber «pnzi2 wlurh aru as a baffer
ar>i ta.ka» T;p th^ «Lo^k viu!tk tbe* pre^^Tire' c*ei tbe* pedu Lf «addciilT refirrcd.
To eomfrl^^ tr^ e<(r;i|Miiei;t «( iht ma^Liue tr^nv t^ aa aaiomatie Fvitch which is
'.f ^rar^ by the f/^d^-wr^td rertical red. aod vL>h pcniiit:^ norent lo enter the
f,r\gr.s^ry wir^iir^ vh^^ the vcrk L^ lightly zripf^d between the <ffcitmd e» and eiits it off
z^ 'ocm a* w»4riir^ heat i^ reaeb^d. In operacion the work i^ H^htly gi iyped between
^h^ '-i^^^rod^^ by the depre^«ion of the pedal cao^in^ the actnadng spring to be com*
pr»^<^. A further depre^ion of the pedal — ^with a re«nhing additional com p r e saon
of tfje •pfiTig — faiLRe'i the «witeh tirj^inz the primary eirrait to be operated, while a
•t.J frrrther depre^^ion of the pedal trrp^ and open« the switch and ftiD further com-
pr^.#-« the •prin^. with the result that the weld l« firmly consolidated.
The maker* claim for their «pot weUer?. of which the foregoing may be eonodered a
t;« pica! example, that tb^ are practically fool-|M^>f. and that they can be operated by
a ^^r•\ girl or other ari.«killed labr>iirer. and that about an hour's practice is all that is
rei^uircd to enable a per-on of average ability to make thoroiighly satL^actory welds
cviTftinuofi^ly on a large variety of repetition w<H'k.
The arrangement of the automatic trip x^witch is shown in Fig. 63. The vertical
a^rtuating bar l'^ !»hown at A. Mounted to slide up and down on it is a tripper carrier B,
whieh can be clamped in any desired position, so as to allow for different thicknesses of
met ^1 being welded and different travels of the electrodes by means of the small hand
!e%'er B^. The trip plnnger C slides in a hole <m the carrier B. and is continualh- being
pre»«ed forward by the action of the spring D. but is prev«ited from being pushed out
iA the hole by reason of the set s^crew C ^. Wlien the actuating bar A is preyed upwards
by the depression of the pedal by the operator, it takes the carrin- along with it and the
trip plunger C engages with the catch piece E. which is clamped in a hcSe formed in the
k/wer p^.rtion of the hinged switch arm F. which is pivoted at G. The catch piece E
can be given any desired amount of projection, and is firmly clamped in position by
roeanM of the bolt E*. The effect of continued depression of the pedal is that the
^witch arm, which isi normally held in the open positi<m by the action of gravity, is
rcnrolved ahout itH pivot and the contact pieces J J' are brought into contact with
the contact pieces H H* respectively, and the primary circuit of the transformer in the
machine is closed. Current then, el course, flows through the secondary winding and
through the metal being welded, since arrangements are made so that the switch is not
clr^scd until the work is firmly gripped between the electrodes. Still further depression
€ji the pedal unll cause the springs K and K^. which encircle the cont<act rods H and H^,
to be com premised to such an extent that the trip plunger C becomes disengaged from
and can slide pant the catch piece E, with the result that the switch flies open and the
circuit is broken. The period of time during which current is permitted to flow may
he regulated by the various adjustments provided. The material of which the contact
nxls of the switch are made is a yellow metal termed by the makers " non-arcing
mortal/' Its composition was not disclosed to us. but we understand that it has been
found to be quite ftucce»ij<ful, no trouble of any kind having been experienced with it.
The other npot welders made vary in certain details from the machine described in
tlHT foregoing, but they all operate on the same fundamental principle.
A typical example of the firm's smaller sized butt welders — ^which represents the
nriachine known as welder B3 — is shown in the drawing Fig. 64. In it the two pieces
of material to be welded are clamped in the gripping jaws A and B by means of the cam
handU'K A* and B* rcHpectively. The jaw B can be reciprocated horizontally by means
of the hand return lever D, which is pivoted to a sliding carriage C. The initial position
RESISTANCE WELDERS OF THE A I MANUFACTURING COMPANY 83
of the lever D can be varied to permit of different distances apart ol the jaws by chang-
ing the length of the hnk D', in which several holes ore formed for the purpose. The
pressure for upsetting the weld is pro-
vided by a spring, wWch is contained in
the sliding carriage C. The initial com-
pression of the spring can be adjusted
by means of the small star wheel E, and
the screw of the spring spindle can be
locked by the star wheel F, It will be
understood that the first motion to the
left of the hand return lever D brings
the two pieces of work into contact.
Further motion of the lever puts more
compression on the spring, and henco
increases the pressure between the pieces
being welded.
The electrical arrangements are
somewhat different from those of the
spot welding machine. There is, in
the first place, provision for only
five working speeds. Then there are
two switches — a push switch and an
automatic switch or circuit breaker.
The normal- position of the latter is
with the circuit closed so that if the
push switch is in, current begins to flow
as soon as the two pieces being welded
come into contact. The movement of
the hand lever and of the sUding carriage
C has the effect of bringing the tripping
piece G into contact with the switch
trip tool, and when a predetermined
point has been reached the piece G
forces open the switch and breaks the
circuit, the arrangements being such
that the switch is thereafter kept open
while the lever is held to the left, since
the tripping piece impinges on the fiat
under surface of the switch trip tool.
When the upsetting of the weld ia com-
pleted the spring push switch is released
by removing the hand from it. The
welded work can then be taken from the
jaws, and the lever D moved to its
starting position.
In oidinary working the amount of
travel of the sUding carriage C is con-
trolled by the adjustable slide stop E, which ensures that when there is no work
in the machine the jaws themselves can never be brought into contact with one
another. For use when it is considered necessary to anneal the welds — as, for
Fio. 61.-"A1" Butt Welder.
W ELECTRIC WELDING AXD WELDIXG AFPUAXCES
in>laooe. vlien dealing with high-carbon ctnJ — aoothtr adjnctaiilr elide itop F,
which i« embodied in the name eaatii^ a« the •-lide stop E. it nraog into the positiim
ot-tiip4«d br the Utter nop and held there br a eateh. The f*op F permits of there
being a greater lei^h betveen the javs than i^ possible vhh the Flop E. «o that
when the current u turned on a greater length o( material is heated. When the
desired tempeiatare is readied the work
» remored from the jaw? and aUowed
to eocd eknrly. We may £av. with regard
to the distance between the jaw? when
weUii^. that the company enunciates
as a rough-and-ready guide that gener-
ally it may be taken that with round
steel a proiection from the jaw? equal
to double the diameter ol the material
will be found to be most satisfactory.
The butt and seam welding attach-
mentii, of which mention has been made
above, are exceedingly ingeniouf. As
far as we are aware, the A 1 C<Hnpany
is alone in the manufacture of these
special attachments for apphcation to
its standMd spot welding machines. It
is, not unnaturally, rather proud of
them, and it draws atteotioa to their
atility in cases in which there is not
more work of all kinds than can be
effected with one machine.
The butt welding attachment does
not caU for detailed deeeription. For
it, the ordinary stakes or arms of the
machine are u^d. The attachment, as
will be seen from Fig. 65, which shows
it applied to a Xo. 4 spot welder, con-
sists of two gripping jaws, one cf which
fits on and can be clamped to the top
stake, the other being fitted on the lower
stake. When in position the clamping
jaws come vertically one above the other
and the pieces to be welded arc held in
a vertical position. The machine is
Fi«.65.-''Al»Bmt Welding Attachment. operated exactly as for spot welding.
The jaw pieces, which are of massive
construction, are not themselves water-cooled, as it is found that the water*
circulating syHtem of the stakes is sufiEcient to keep the jaws sufficiently cool for
intermittent working. The bulk of the metal in the two portions of the attacliment
in brasK, but the actual jaws in which the work is gripped are made of a readily
renewable piece of copper on that side through which the current flows and of steel
on the side on which the clamping pressure is applied. The initial distance apart
of the jaws can be varied from J in. to 2 in. by means of the milled nut on the
vertical npindle seen at the right-hand side of the top jaw.
RESISTANCE WELDERS OF THE A 1 MANUFACTURING COMPANY 95
The seam welding attachment must be deficribed at greater length. First of all, it
may be Baid that it is made in various forms. There is, for Instance, one in which the
welding operation is performed longitudinally straight in towards the body of the
machine, and in it the top roller only is revolved. We show an example of .it in Fig. 66.
In another form, which is for circular welding, the rollers are mounted at right angles
to their carrying arms. In still another the lower arm is made right-angular for such
work as the circular welding of the ends of tins. Finally, there is a form in which both
Fio. 66.— "Al" Seam Welding Attachment.
the bottom and top rollers are power driven. For thin work, such as -^g in. added
thickness, it is not necessary for the lower wheel to be power driven, but with heavier
work power driving is advisable in order to prevent " plucking " of the metal while it is
at welding heat.
We cannot spare the space to describe each particular form in detail, and we propose,
therefore, to confine our remarks to the form illustrated in Pig. 66, which illustrates
the seam weWer attachment known as No. S 4a as applied to a No. 4 spot welder. The
latter machine is slightly different in construction from the spot welder described
above, which in that known as No. 2.
The general arrangement and working of the apphance may be readily understood
96 ELECTRIC WELDING AND WELDING APPLIANCES
from the illustration. The bottom stake of the spot welder is remDved and its place
taken by an arm which carries the lower roller. The portion carrying the upper roller
is slipped on to the upper stake, from which, of courne, the electrode has been removed.
When in the correct position the appliance is securely clamped on the stake by means of
the nut seen at the top. Power is appUed through a belt drive on to a shaft from which a
short countershaft is also driven by belt. The countershaft, which has three speed
cones, carries at its end a toothed bevel wheel, which meshes with a bevel wheel carried
on a spindle at the other end of which ia a worm meshing with a worm wheel on the
short spindle, which, in its turn, meshes with a worm wheel on the ahort'spindle carrying
the upper wheel.
The upper roller is attached to a large block of copper, and is water cooled, there
being a thin sheet of copper between the revolving roller and the water reservoir. The
lower roller is also water cooled. In the illustration given the water nozzles are shown
clearly. In another form of the attachment the nozzles are at the rear of the lower
roller carrier arm, and the water is sprayed through a small jet into a small tank or
trough in which the lower half of the roller dips.
In the form of attachment in which the lower roller is pow^r driven the drive is
obtained by means of a chain from the upper shaft to a point at the ro6t of the lower
arm, the chain then being taken along the inside of the lower arm to the roller.
It will not be necessary to iUustrate or describe at any great length the firm's seam
weldiftg machines proper. They are, in principle, substantially similar to the seam
welding attachments, and they are operated in very much the same manner as are the
spot welders, saving that pressure is kept on the pedal during the welding of the whole
length of seam, the current of course being allowed to flow during that period also, and
not being cut off as in spot welding. In the smaller machines only the top roller is
revolved by power, but in the larger sizes both rollers are power driven. There is also a
pedal-worked clutch, by means of which the rollers may bestarted or stopped. With
the rollers not revolving a quick depression and release of the arm-cperating pedal will
cause the formation of a " tack " weld, this being intended to do away with the neces-
sity for a separate spot welder for " tacking.'* The welders are furnished with plug
boxes having fast and slow plugs, as well as four additional plug holes, so that eight
heating speeds are available. The top arm carrying the roller is, as in the spot welders,
hinged at the welding level of the bottom roller, so that a straight pressure may be
obtained on the weld, and no current flows through the hinge. The standard top arm
is not water cooled, but the revolving roller is cooled as in the seam welding attachment.
The standard bottom arm is cooled as in the alternative method referred to in connec-
tion with the seam welding attachment, the roller actually revolving in a small water
trough. The standard machine has 9 in. arms, but arms up to a maximum of 36 in.
can be fitted. The maximum capacity for which the machines are built is 10 kilo-
watts. The pressure applied to the work can be adjusted in the same manner as in
the firm's spot welders.
In addition to making welding machines, the firm supplies various accessories,
including rotary converters, generators, switchboards, switches, etc. In particular,
it makes a rotary converter for transforming direct current at 460 volts to alternating
current at 230 volts. This machine, which is of 16 kilovolt-ampere capacity and runs
At 1500 revolutions per minute, is designed to operate three of the firm's No. 3 welders.
CHAPTER XIV
THE STRENGTH OF ELECTRIC WELDS
The question of the strength of electric welds is, naturaUy , of first-class importance, and
it has in consequence received a considerable amount of study. The matter id of great
complexity by reason of the varying conditions under which the process is carried out,
as well as of the different systems of welding which are available. We shall not attempt,
therefore, to discus^ it in all its bearings ; indeed, there are not sufficient data in exist-
ence to enable such a course to be taken. Nevertheless, very valuable investigations
have been carried out, both in this country and abroad, and we propose briefly to review
some of them. We would preface our remarks, however, by repeating that, in our
opinion, finality has by no means been reached, and that it would not surprise us if
the figures, which will be found in what follows, were to be considerably modified when
the whole subject has received the more extended research which it undoubtedly
deserves.
As might have been anticipated by aU who have had any experience of the methods
of Lloyd's Register, which is always willing to give trial to novel methods, that institu-
tion, as soon as the application of welding to ship construction was mooted, decided to
carry out an exhaustive series of tests with a view to ascertaining whether a set of
rules, under which electric welding might be employed in shipbuilding, could be formu-
lated. The original tests occupied a period of some six months, and they resulted in
the issuing in August, 1918, of '^ Tentative Regulations for the Application of Electric
Arc Welding to Ship Construction." The actual regulations do not concern us at the
moment, but the general nature of the experiments performed and the conclusions
which they led to may be profitably given. This we are enabled to do by the courtesy
of the Secretary of the Society, who communicated to us the decision of the Greneral
Committee as soon as it was arrived at. We may say here that those who desire to
follow the matter more closely than we are, by reason of space, enabled to do in the
present instance, may do so by perusing a paper entitled " Experiments on the Applica-
tion of Electric Welding to Large Structures," which was read before the Institution
of Civil Engineers on March 11th last, by Mr. Westcott Stile Abell.
It appears that the general scope of the experiments included : (a) Determina-
tion of modulus of elasticity and approximate elastic Umit ; (6) determination of
ultimate strength and ultimate elongation ; (c) application of alternating stresses
with (1) rotating specimens, (2) stationary test pieces ; (d) minor tests, such as.(l)
cold bending of welds, (2) impact tests of welded specimens ; (e) chemical and micro-
scopic analysis.
The tests were carried out on specimens which were as large as possible, particu-
larly in connection with the static determinations of elasticity, ultimate strength
and elongation, some of the test specimens being designed for a total load of just
under 300 tons. The advantage of these large specimens was that the effect of work-
manship was better averaged and the results were more comparable with the actual
work likely to be met with in ship construction. For alternating stresses the specimens
were relatively of small size. For the rotating test.pieces, circular rods^ mainly
S.W. u
98 ELECTRIC WELDING AND WELDING APPLIANCES
machined from a welded plate, were used, the diameters selected being 1 in. and | in.
These bars, about 3 ft. in length, were attached to a lathe headstock, and a pure
bending movement in one plane was applied by means of two ball races to which
known weights were attached. The material of the bar was thus exposed alternately
to maximum tension and to equal maximum compression once in each revolution.
The machine was run at about 1060 revolutions per minute. Bars of identical material
were tried in pairs, one specimen welded and the other unwelded, and the number
of revolutions before the specimens parted was observed for various ranges of stresses
varying from ±15 tona to ± 6 tons.
In the second series of alternating stress experiments flat plates of three thicknesses,
viz. I in., I in. and ^ in., were used. These specimens were tried in groups of four,
each group consisting of one plain, one butt welded, one lap welded and one lap riveted
plate. The specimens, which were about 14 in. long by 5 in. broad, were clamped
along the short edges, so that the distance between the fixed lines was 12 in. Each
plate was also clamped, near the middle, to the end of a pillar, which by means of a
crank arm was caused to oscillate and to bend the specimen equally up and down by
adjustable amounts, the maximum total movement in any of the experiments tried
being -j^ in. The machine was run at various revolutions — ^not exceeding 90 per
minute— and the number of repetitions at which the specimen parted was obser^^ed.
Minor tests of various kinds were undertaken, of which the principal had reference
to the suitability of the welded material to withstand such bending and shock stresses
as might occur in the shipbuilding yards. The experiments on bending consisted of
doubling the welded plate over a circular block of diameter equal to three times the
plate thickness, and comparing the results with those of the plate of the same material
but unwelded.
In the impact tests heavy weights were dropped from various heights on to the
welded portion of a plate 5 ft. in length and 2 ft. 6 in. in breadth, the weld being across
the plate parallel to tli^e shorter edge. The deflections were noted and the condition
of the weld was examined after each blow. The chemical and micrographical examina-
tion followed the ordinary practice.
The results arrived at are summarised in the following : —
(1) Modvlua of Elasticity and Approximate Elastic Limit. — (a) In a welded plate
the extensions in the region of the weld are sensibly the same as for more distant por-
tions of the unwelded plate. (6) With small welded specimens containing an appreci-
able proportion of welded material in the cross-sectional area, the relation between
extension and stress is practically the same, up to the elastic limit, as for similar
unwelded material, (c) The elastic limit, or the limiting stress beyond which extension
is not approximately directly proportional to stress, appears to be slightly higher in
welded than in unwelded material, (d) The modulus of elasticity of a small test piece,
entirely composed of material of the weld, was about 11,700 tons per square inch, as
compared with about 13,500 tons for mild steel and about 12,500 tons for wrought
iron.
(2) Ultimate Strength and Ultimate Elongation, — (a) The ultimate strength of welded
material with small sp^imens was over 100 per cent, of the strength of the unwelded
steel plate for thicknesses of J in., and averaged 90 per cent, for plates of f in. and
1 in. in thickness. (6) Up to the point of fracture the extensions of the welded speci-
mens are not sensibly different from those of similar unwelded material, (c) At stresses
greater than the elastic limit, the welded material is less ductile than mild steel,
and tlfe ultimate elongation of a welded specimen when measured on a length of
THE STRENGTH OF ELECTRIC WELDS 99
8 in. only averages about 10 per cent., as compared with 25 to 30 per cent, for
mild steel.
(3) Alternating Stresses. — (a) Rotating specimens (round bar) : (1) Unwelded
turned bars will withstand a very large number of repetitions of stress, exceeding, say,
5 millions, when the range of stress is not greater than from 10^ tons per square inch
tension to 10^ tons per square inch compression ; (2) welded bars similarly tested will
fail at about the same number of reversals when the range of stress exceeds ± ^ tons
per square inch, (b) Stationary test pieces (flat plate) : (1) Butt welded specimens will
withstand about 70 per cent, of the number of repetitions which can be borne by an
unwelded plate ; (2) lap-welded plates can endure over 60 per cent, of the number
of alternations necessary to fracture a lap-riveted specimen.
(4) Minor Tests, — (a) Welded specimens are not capable of being bent, without
fracture, over the prescribed radius to more than about 80 deg. with ^ in. plate, reduc-
ing to some 20 deg. where the thickness is 1 in. Unwelded material under the same
conditions can be bent through 180 deg. (6) Welded plates can withstand impact with
a considerable degree of success ; a | in. plate, 5 ft. in length by 2 ft. 6 in. in width,
sustained two successive blows of 4 cwt. dropped through 12 ft., giving a deflection of
12 in. on a length of about 4 ft. 6 in. without any signs of fracture in the weld.
(6) Chemical and Microscopic Analysis. — (a) Chemical analysis : (1) The electrode
was practically identical with mild steel, but there was a greater percentage of silicon ;
(2) the material of the weld after deposition was ascertained to be practically pure
iron, the various other contents being carbon .03, silicon .02, phosphorus .02 and
manganese .04 per cent, respectively. (6) Microscopic examination : (1) The material
of the weld is practically pure imn ; (2) the local effect of heat does not appear largely
to affect the surrounding material, the structure not being much disturbed at about
-^ in. from the edge of the weld (the amount of disturbance is still leds in thin plates) ;
(3) the weld bears little evidence, if any, of the occurrence of oxidation ; (4) with welds
made as for these experiments, i.e. with flat horizontal welding, a sound junction is
obtained between the plate and the welding material.
(6) Strength of Welds {Large Specimens). — (a) Butt welds have a tensile strength
varying from 90 to 95 per cent, of the tensile strength of the unwelded plate, (b) Lap
welds : (1) With full fillets on both edges the ultimate strength in tension varies from
70 to 80 per cent, of that of the unwelded material ; (2) with a full fillet on one edge
and a single run of weld on the other edge the results are very little inferior to those
where a full fillet is provided for both edges, (c) Riveted lap joints : For plates of
about i in. in thickness, the specimens averaged about 66 to 70 per cent, of the strength
of the unperforated plate.
There are two points in connection with the foregoing which call for mention.
The first is that the experiments only referred to work effected by arc welding, and
the second that only one particular form of coated electrode was employed. In this
connection it may be mentioned that the '^ Tentative Regulations " provide that
(a) the process of manufacture of the electrodes must be such as to ensure reliability
and uniformity of the finished article ; (6) specimens of the finished electrodes, with
specifications of their nature, must be supplied to the Committee ; (c) that the Com-
mittee's officers shall have access to the works where the electrodes are made, so as
to ensure that the electrodes produced are identical with approved specimens ; and
(d) that no alteration in the method of manufacture may be adopted without the con-
sent of the Committee. It is quite obvious, therefore, that the Committee attaches
great importance to the question of electrodes.
Early in last year Captain (now Major) James Caldwell, R.E., Deputy Assistant
100 ELECTRIC WELDING AND WELDING APPLIANCES
Director of Materials and Priority at the British Admiralty, was, at the request of the
United States Shipping Board, lent to the Emergency Fleet Corporation. At the
conclusion of three months* service Captain Caldwell issued a voluminous report on
** Electric Welding and its Applications in United States of America to Ship Construc-
tion/' Included in the report is a lengthy table setting out the results of an extensive
series of tests carried out under the direction of Mr. W. T. Bonner, of the Chester
Shipbuilding Company. In order to be fully appreciated, the whole of the information
given in the table should be taken into consideration, but, as space will not permit
of us to reproduce the table in extenso — ^it would take a page and a half of the Engineer,
and even then be reproduced to a small scale — ^we must content ourselves by giving
the following summary. The starting-point is an ordinaiy single-riveted lap joint
effected in accordance with Lloyd's regulations, one seam being caulked. The thickness
of the plates employed varied from .234 to .30 square inch, the width from 9 in. to
9|ij^ in., and the area involved froxa 2. 106 square inches to 2.719 square inches. The
mean of a series of tests made on joints of this type and size showed that the riveted
plate had a tensile strength of about 52 J per cent, of the strength of an unperf orated
plate of like size and form. For simplicity's sake we will call this joint A. A double-
riveted joint, singly caulked, of approximately the same dimensions was found to
give a mean of 76^^ per cent, of the strength of an unperforated plate. A joint similar
to A, but with one seam welded instead of caulked, gave as a mean a strength of 71^
per cent of the unperforated plate. With a similar joint, but with a full fillet weld, the
percentage rose to 75^-. A lap joint of veiy similar dimensions to A, but with a fillet
weld at both plate edges and no rivets, gave as a mean of several tests a strength of
94 per cent, of unperforated plate of equal dimensions. A butt-Welded joint furnished
with a strap fiUet-welded at both edges, but no rivets and having dimensions com-
parable with those of joint A, gave as the result of several tests a mean strength of
95^ per cent, of that of unperforated plate. The foregoing tests were apparently
made with the joints just as they were left by the welder, for later in the table are
given side by side examples of butt joints before and after being machined. The joint
before machining gave in the two cases recorded a strength equal to 100 per cent, of
that of unperforated plate, while the two cases of machined joints showed strengths
of 70^^ and 77^ per cent, respectively.
In the case of all the foregoing arc welding was employed, but there is no indica-
tion as to what type of electrode was used. There is only one set of tests in which
the specimens were spot welded. The joint was of the lap type, had a length of 10 in.
and an area of 3.08 in., the thickness of the plate being 0.308 in. The strength of
the joint was found to be only 6 per cent, or under of the unperforated plate, and the
remark is made the efficiency was " too low for serious consideration." This is inter-
esting in the Ught of the results which we shall now refer to.
In the April, 1919, number of the Proceedings of the American Institute of Electrical
Engineers there is printed a paper on " Welding Mild Steel," which was read by Mr.
H. M. Hobart at a joint session of the Institute with the^ American Institute of Mining
Engineers held at New York on February 20th, 1919. The paper deals principally
with the investigations undertaken by the Welding Research Sub-committee of the
Welding Committee of the Emergency Fleet Corporation, and it forms a valuable
contribution to the literature on the subject. With the bulk of it we are not at the
moment concerned, but there is one portion of it which deals with the strengths of
various types of joints that bears directly on .the matter which we have under con-
sideration. Mr. Hobart points out that a great deal of progress is being made in
America in the use of spot welding as a means of joining thick plates. It is believed.
THE STRENGTH OF ELECTRIC WELDS
101
he remarks, that spot welding has a great future as applied to shipbuilding, and
several large welders have been built for shipyards.* "In some of its applications/'
he continues, '^ spot welding affords a method of preliminarily jointing the hull
plates, after which the additional strength is provided by arc welding. The Welding
Research Sub-committee has already made some progress in comparing combined
spot and arc welds and combined rivet and arc welds with riveted, spot-welded,,
and arc-welded joints. It is not a question, in such an investigation, of spot versus
arc welding, but of cpot and arc welding."
In the tests alluded to the specimens were made up of the following combination : —
(1) Spot and welded fillet, as in ^
A in the^ accompanying diagram, /r^^^~y^''yji j^r^^^T P^
Fig. 67. // f "\ f ,f-^ / y
(2) Fillet welded, made by
welding fillets about 2 in. in length A- Fillet and Spot Welded
at the ends of the plates, as in B.
(3) Riveted and fillet welded,
as in C.
(4) Spot welded, made by weld-
ing two spots approximately 1 in.
in diameter on the plates, as in D.
(6) Riveted joint made by rivet-
ing a J in. by 4 in. by 12 in. plate
with two plates \ in. by 4 in. by
16 in., using two | in. rivets and
a 4 in. lap.
The ultimate loads borne by these
joints were as follows : —
(1) Spot and fillet welded, 60,360 lb.
(2) Fillet welded, 37,000 lb.
(3) Riveted and fillet welded,
35,000 lb.
(4) Spot welded, 28,000 lb.
(5) Riveted joint, 13,000 lb.
llMynruJ/
B -Fillet Welded
C —Riveted and Fillet Welded
I) -Spot Welded
12'
£ — Riveted Joint
Fig. 67. — Welded and Riveted Joints.
It is not quite clear why No. 3 should be less than No. 2, but possibly were a larger
number of test pieces to be made than was actually the case the figures might show
some modification. A noticeable feature is the strength of the spot-welded as compared
with the riveted joint. It would seem likely that in the tests made under the super-
vision of Mr. Bonner, and quoted above, the strength of the spot welding machine
ufied was not great enough to deal adequately with plates of the thickness which he
was employing.
The foregoing embodies some of the latest published data regarding the strength
of various types ol electric welds. In it, however, it has been possible to do no more
than touch upon the fringe of what is really a very wide subject. It has to be realised
that in electric welding, and especially in arc welding, the personal element counts
for a great deal. It is, unfortunately, by no means easy to ascertain by inspection
after it has been made whether a weld is good or not. An efficient and experienced
* There is little doubt that Mr. Hobart was referring to the machines described in Chapter XI.
102 ELECTRIC WELDING AND WELDING APPUANCES
arc welder wiU be able to tell as he is making the joint whether the joint is good or
bad. The inexperienced welder may not be able to do so, and he may yet produce
work which to outward seemiiig is good. As we pointed out in an earlier chapter,
however, there is no guarantee that a welded joint made by a smith in the ordinary
way is sound throughout. A good smith will make it so. While an inefficient smith
may leave impurities between the surfaces he is trying to weld. In fact, it may be said
that after taking everything into consideration the evidence available seems to in-
dicate that in the various forms of electric welding the predent-day engineer has at
his command methods of joining metals together which, if properly applied, are in
most cases at least as efficient as, and in some instances more efficient, than any which
have gone before. In saying this we do not wish to be taken as minimising the value
of acetylene welding. On the contrary, we are satisfied that, in some directions, the
acetylene torch is the most efficient tool which can be employed. We are convinced,
however, that a good deal of weeding out is required and that a not inconsiderable
amount of improvement of existing methods will have to be effected before the full
benefits derivable from electric welding can be experienced. Such weeding out is
bound to be done, however, and such improvements are certain to be brought about,
so that the engineer of the future will most certainly possess more perfect methods
than those which exist at the present day, excellent as, in most ways, they are.
CHAPTER XV
A LARGE BRITISH SPOT-WELDIXG MACHINE
In that chapter of the series on " Electric Welding and Welding Appliances " in which
we dealt with the machines and processes of Pontelec Welding Patents, Limited,*
we made mention of having seen the drawingls of a large spot-welding machine which
was, at the time the chapter was written, under construction. The maohine has now
been completed, and it is believed by its makers to he the largest spot welder o£ its
type which has up to now been constructed for commercial purposes in this country.
Fia. 68.— Pontelec Spot Welder, with Stakes ar»nged horizontalty.
The particular work which it was designed to perform is the spot welding of tubes in
6 ft. lengths mode of { in. steel plates, and having an internal diameter as small as 8 in.
Naturally, however, larger diameters can be dealt with. In the two views of the machine
which are given in Figs. 68 and 69 it will be observed that the design is such that the
• 3eeChftpt«rV.
104 ELECTRIC WELDING AM> W'ELDIXG APPUAN'CES
etakefl or anna can either be used in a vertical or a horizontal position. The body of the
machine ift hinged to the bed by bolts, one of which, with its nnt, oan be seen at the
left top corner of the nde frame in both Ulustrations. When the Bt^es are horiz<»ital
the body is held in poeition by means of two eye-holed pinB, which pass throngh boles
in the side frames and enter similw holes formed, one on cme side and the other on the
other of the framework of the body of the machine. When it is desired to have the arms
vertical, the weight of the body of the machine is taken by means of a crane, the hook of
which is passed through the eye-bolt seen at the top. The supporting pins can then be
withdrawn, and the body of the machine is allowed to hinge down ao that it enters the
space between the side frames of the
base. When the stakes are vertical,
holes in the body of the machine-~one
of which is seen at the top, just to the
left of and below the eye-bolt in Fig. 68
— register with holes in the side frames
— one of which b seen at the right top
comer of the side frame in Fig. 68 —
and the pins, which were removed just
before lowering commenoed, can be
inserted. When in either the horizontal
or vertical positions the weight of the
body is taken on four pins, one at each
comer. The pins are 2 in. in diameter,
and hence of ample strength to support
the heavy weight of the body. The
total weight of the machine is, we may
say here, in excess of 4^ tons, some
H tons of which is represented by copper.
The construction of the machine will
be readily seen from the illustrations.
The bed is made up of two side plates
and two end plates, all of cast iron, and
all bolted seeurely together. The body
part, which supports the stakes or
electrode arms and contains the trans-
former, is composed of cast iron end
Fio. 69, pieces separated by and bolted to cast
The Welder, with Stakes arranged verticaUj. iron pillars, which are star-shaped in
cross section. The transformer core is
built between and is supported by these pillars. The end pieces have each cast in the
centres of their ends semicircular chaimels, which are more or less in the form of
plummer blocks, and which are machined to a radius of 3| in. Bo as to receive the
stakes. The latter, which are 6| in. in diameter, are secured in position by means of
caps bolted on in the same manner as are the caps of bearings. The caps at the front
side of the machine — that is, the side from which the stakes project — are of copper, and
to them are connected the terminals of the secondary winding of the transformer. The
ca{)s at the back side are of cast iron, since they are not required to carry any current.
The primary of the transformer is fomished with ten tappings, so that a wide range
of welding speeds is obtainable.
As it was necessary for the machine to have such a wide reach as 5 ft., special
A LARGE BRITISH SPOT-WELDING MACHINE 106
consideration had to be given to the construction of the stakes. It was realised from
the outset that pure copper alone would not give the requieite stiffness, but would
have excessive " spring." On consideration, it was decided to use cores of manganese
steel with electrolytic copper, containing a small amount of silicon, oast on them. For
the cores Hadfield's Hecla manganese steel bull-headed railway rails, weighing 95 lb.
per yard and rolled in accordance with the British Standard Specification, were em-
ployed. As showing the degree of stiffening imparted to the arms by the rail rein-
forcement we may say that we understand that with a load of from 10 cwt. to 1 5 cwt. at
5 ft. extension the " spring " does not exceed J in. The arrangement of both top and
bottom arms is shown in Fig. 70. Both fums are of the same diameter, and both are
machined so that they can be slid backwards and fOTwards in their bearings when the
caps of the latter are slacked off. The top arm has an extreme length of 7 ft. 3 in., and
is parallel from end to end . The rail reinforcement is taken to within 3 in. of the extreme
forward end, and it projects 1 in. at the rear end. The lower arm has an overall length
of 7 ft. 9J in. Its sides are parallel for a length 5 ft. 1 in. from the rear end, and in the
remaining 2 ft. 8^ in. the sides of forward portion are machined off taperwise until, as
Fis. 70. — Upper and Lower Stakea or Arma.
may be ^een in the drawing, the distance between them is only 4 in. Two inches from
the extreme front end a vertical hole 2 in. in diameter is drilled for a depth of 4} in.
for the reception of renewable eleotrodes, the projection of which above the top of the
arm can be adjusted by means of a set screw 1 in. in diameter, for which a tapped hole
is formed concentrically with and at the bottom of the hole containing the electrode.
A ^ in. slot is cut vertically in the end of the arm for « depth of 6^ in., and a horizontal
hole is drilled in the arm at a distance of 4 in. from its end, so that by means of a bolt
and nut the electrode may be firmly gripped. The rail reinforcement is only taken to a
point 9^ in. of the front end, the remainder of the arm beii^ copper. There is a pro-
jection of 1 in. of the rail at the rear end, oe in the upper arm. The lower arm has two
grooves 1 in. wide and I in. deep, with their bottoms curved to ^ in. radius, formed one
on each side of the horizontal diameter. These grooves are intended for the accommo-
dation of pipes for carrying water for cooling purposes should they be found necessary.
We gather, however, that, so far, artificial cooling has not had to be resorted to, the
large mass of copper in the fums having proved ample for the conduction away of the
heat during working. It should be mentioned, though, that up to the present the
machine has not been worked to its full capacity. The maximum energy at the dis-
posal of the Ponteleo Company for testing purposes is otdy 50 kilovolt-amp^res. With
106 ELECTRIC WELDING AND WELDING APPLIANCES
that amount of energy we understand that the maohine has satisfactorily welded jt m-
plates — or an added thicknesa of J in. — with the arms fully extended. It is thought
probable, however, that when sufficient power is available the machine will readily
weld two ^ in. plates — or an added thickness of 1 in. The current regulation is such
that, at the other end of the scale, sheets as thin as No. 22 gauge can be dealt with.
The makers point out that it is not, of course, necessary that the electrode-carrying
arms should be circular in section. In the present case the form was practically settled
by the fact that the tubes, which the machine was specially designed to weld, were
only 8 in. in diameter, and because it was desired to have the gap adjustable in height.
"The ENCi.tEll" SwA.-. St T-l EMi^tin" »— « St
Flo, 71. — Arrangement of Electrode Slide. Fio. li. — Arrangement of Transformer.
It will be understood, of course, that by slacking away the caps holding the arms in
position the length of projection of the latter can be altered at will. We gather that
the minimum projection gives a free-reach of only about 9 in.
The upper electrode arm remains, as may be gathered from the illustrations, rigid,
and is nob moved up and down, as in some forms of spot welders. It is the electrode
which is reciprocated, and the means by which the reciprocation is effected is clearly
shown in Fig. 71. It will be observed that the electrode A, which is 2 in. in diameter,
is inserted in a hole drilled in the extremity of a soUd copper sliding piece B. The
latter, which has, in cross section, the form of a truncated cone, fits into and can be
moved up and down or backwards and forwards, as the case may be, in a slide of
exactly similar shape as itself, which is formed by a body C and a cap D. the latter
being securely attached to the former by means of screwed bolts. The sliding piece.
A LARGE BRITISH SPOT-WELDING MACHINE 107
body, and cap are of copper, the studs of brass, and the nuts only of iron. The
extremity of the upper electrode arm E fits into a boss F fonned on the body C, and,
since there is a slot G cut in the periphery of the latter, the electrode arm can be
gripped tightly by means of the bolt and nut H.
Housed in a channel formed in the sliding piece C is a spring J, and arranged in a
channel 2| in. wide and | in. deep cut in the sliding piece is a toothed rack K, which
is furnished at its upper end with a right-angled extension L. The latter is bored and
tapped to receive the screw M, at the end of which is an enlarged portion N, which
impinges on the top of the spring J. By means of this arrangement any desired
initial compression may be put upon the spring. Meshing with the toothed rack is a
toothed pinion O, which is keyed to the shaft P. The shaft can be rotated by means of
the lever seen in Figs. 68 and 69, the baleinced weight on which is so arranged that the
tendency is always to draw the upper electrode away from the lower. It will be under-
stood that the effect of moving the lever is to push the electrode down on to the work,
further depression giving greater conapression to the Spring, and hence greater pre^ure
on the work. The makers point out that, of course, sway other mechanical means of
exerting the pressure necessary for welding, as weU as compressed air or hydraulic
pressure, can be applied to take the place of the mechanism illustrated.
The winding of the transformer is for 50-period alternating current at 160 volts,
though, naturally, any other winding to suit different conditicms can be applied. The
primary circuit is closed and opened by means of a foot-operated switch. In Fig. 72
we show the outline of the arrangement of the transformer for a machine of similar
size.to that described in the foregoing, but with a permanent base for horizontal work
only. The electrical connections are, however, identical in both cases.
CHAPTER XVI
THE PLASTIC-ARC WELDING SYSTEM
The Plastic-arc welding system is the name given to the process of electric arc welding
which is controlled by the Wilson Welder and Metals Company, of 2 Rector Street,
New York City. It was by means of it that the German steamships which were in-
terned in harbours in America, and. which had been wilfully and seriously damaged
by their crews, were repaired. Before describing the system itself, it will perhaps
be of interest to our readers if we briefly refer to the manner in which the vessels were
damaged and to the steps taken to repair the breakages.
Oh the declaration of war the United States authorities took over all the enemy
ships which had been interned in various ports in the country. There were 103 vessels
in all. In the port of New York alone there were interned 31 steamships, of which
27 were Grerman and 4 were Austrian. Of the 27 German vessels 2 were sailing ships
and 4 were small steamers. The latter had evidently been considered by the Germans
to be of comparatively small importance, for the destruction wrought in them was but
slight ; but the remaining 21 vessels, which ranged in size from the 56,000 tons or so
of the Vaterland to the 3900 tons of the Nassovia, had been so seriously damaged that,
when taken over by America, they were entirely valueless for transport purposes. The
Germans, with the thoroughness which characterises them even when engaged in work
of destruction, had so mishandled the machinery that in no case was there an engine
which could turn round. A survey showed that of the 20 vessels in New York Harbour
which were fitted with reciprocating engines — ^the Vaterland ik turbine-driven — there
were 118 fractures of an important character, which would, had ordinary repair
procedure been followed, have necessitated the replacement of seventy steam cylinders.
As a matter of fact, it was at first proposed to proceed with such replacement, but
when the question had been further investigated it was realised that the length of
time required to carry out the repairs in that manner would be prohibitive if the ships
were to be used for the transport of troops across the Atlantic so ad to be of any real
service in the war. The principal damage done, according to a report made by the
Secretary of the Navy, was the breaking of cast iron parts of the main engines —
chiefly the cylinders — ^though in one case piston-rods, connecting-rods, and boiler
stays were sawn half-way through, and in others the boilers were ruined by dry firing.
There was, in addition, much vandalism of a minor character, but the task of remedy-
ing it was insignificant in comparison with the gigantic business of repairing the
cylinders, some of which were more than 9 ft. in diameter. The methods of destruction
adopted were various. Apparently dome sort of a battering-ram bad been exten-
sively employed, and if that apparatus were not by itself capable of doing what was
required of it numerous holes were drilled, in some cases a complete line of holes
being made round the part at which the battering-ram was being appUed. The different
kinds of damage were, however, too numerous to be described in detail in the present
instance. We can only refer to the engravings Figs. 73 to 76 inclusive, which are
reproductions of certain photographs of different pieces of machinery in various vessels
taken before the work of repair was commenced.
MACHINERY IN GEEMAN LINERS, SHOWING DAMAGE
DONE BY CREWS
Via. 73. — S.S. Gtorge I^athington — Fractured Circulating-Pump Casing.
Fio. 74.-S.S. Frinz /oacftim— Broken Cylinder-Head and broken Low-Preadure Cylinder.
MACHINERY IN GERMAN LITERS— contmued.
Fio. 76.— S.S. Kaiter WiUttlm /7,— Fractured Low-Pressure Cylinder Liner.
Fro. 76.— S.S. FriedHch der (Trom— Broken Steam InUke Second Intennediate Cylinder
THE PLASTIC-ARC WELDING SYSTEM 111
The credit of having suggested that the repairs might be effected by means of arc
welding is attributed to Capt. E. P. Jessop, of the United States Navy, the Engineer
Officer of the New York Navy Yard, to which place a few of the vessels were trans-
ferred for repair in the first instance. His recommendation was readily endorsed by
Bear- Admiral Burd, the industrial manager of the yard. The matter was referred to
the Bureau of Steam Engineering, and Capt. O. W. Koester, assistant to the Bureau,
was directed to make a thorough examination of all the conditions on the ex-German
ships. As a result of his investigation, orders were issued to make all the necessary
repairs, where possible, by electric welding, and to resort to mechanical patching only
where welding was impracticable.
It is explained by the Secretary of the Navy, in his report for the year ending
December 1st, 1918, that the '^ decision, so far-reaching in its application and so fraught
with danger to the professional reputation of the officers concerned," was come to in the
face of opposition from engine builders and marine insurance companies, but that it
was made " with such confidence in the ultimate result as left no room for doubt of
its success." Yet, though, of course, electric welding had been in successful operation
for some considerable time in connection with ship repairs, it had never before been
employed on such an extensive scale as was then proposed. It was realised, however,
that if it could be successfully applied, it would not be necessary to remove the cylinders
from the vessels, and it was calculated that the ships would be ready for service
months earlier than would be the case if the cylinders were taken out and replaced,
and, further, that there would be a great saving in money.
The decision was fully justified by the results attained. " So well and so success-
fully were the repairs accomplished that," states the Secretary of the Navy, " there
was not a single instance of a defective weld, nor has one developed during the months
of arduous service on which these ships have been engaged." And he continues, '' as
a sidelight on this work it has been made the subject of careful estimate and deter-
mination that the repair of these ships resulted in the saving qi twelve months in time,
enabled us to transport at least 500,000 troops to France, and effected an economy
which is conservatively estimated at upwards of 20,000,000 dols."
We understand that the cylinders of fifteen of the vessels were repaired by electric
welding, while those of six were repaired by fitting mechanical patches. . In other words,
eighty -two of the major injuries were repaired by welding and thirty-six by mechanical
methods. We are informed that the whole of the welding work in connection with,
the vessels shown in the accompanying table (see page 112) was effected on the Wilson
system, which we shall now proceed to describe.
The first sixteen vessels in the above table, representing over 288,000 gross tonnage,
were made available for the transport of American troops and supplies overseas ^within
the space of five and a half months. The first two ships to be tackled — ^the Friedrich
der Grosse, now the Huron, and the Prinzess Irene, now the Pocahontas — were ready
for sea within two months from the time that the repairs were undertaken, in spite
of the fact that their engines were among the worst damaged of aU — ^so badly, indeed,
that with ordinary -methods nine cylinders would have had to be replaced.
The sole agents in this country for Plastic-arc welding plant and apparatus are G. D.
Peters and Co., Limited, of 15 Dean's Yard, S.W. 1, and of Windsor Works, Slough.
At the latter we recently had an opportunity of witnessing the system in operation
within a day or two of its having been got to work. The current was supplied by an
ordinary motor generator set, the generator being compound wound with interpoles
and designed to generate direct current at 37 volts. There is nothing special in either
the motor or the generator, nor are they electrically connected. The gist of the system
112
ELECTRIC WELDING AND WELDING APPUANCES
lies in the control panel, which is illustrated in Fig. 77, and the connections of which
are shown in Fig. 78. The panel is equipped for both welding and cutting, but it is in
the connections for welding that its chief interest lies, since, when used for cutting,
only the reactance coil, the resistance grid shown at the left-hand bottom corner of
the illustration, and the ammeter are in circuit. When, however, the connections
are set for welding — ^that is, when the double-pole knife edge switch is, as shown
in the left top comer of the engraving. Fig. 77, thrown over to the right-hand contacts
— other pieces of apparatus, which differ from those of any other system with which
we are acquainted, are brought into play. On tracing the connections shown in Fig.
78, it will be observed that the positive terminal of the generator is connected directly
— and without passing through any apparatus saving the knife switch and plug switch
E — ^to the work. The negative pole, on the other hand, runs from the knife switch
VESSELS REPAIRED BY THE WILSON SYSTEM.
German name.
Grosser Kurf urst
Kaiser Wilhelm II
Amerika . .
Neckar
Cincinnati
(Jeorge Washington
Friedrich der Grosse
Vaterland
Koenig Wilhelm II
Martha Washington
Barbarossa
Kronprinzessin Cecelie . .
Prinzess Irene
Hamburg
President Grant
President Lincoln
Saxonia
Rhein
Bulgaria
U.S. name.
Aeolus
Agamemnon
America
Antigne
Covington
George Washington . .
Huron
Leviathan
Madawaska
Martha Washington . .
Mercury
Mt. Vernon
Pocahontas
Powhatan
President Grant
President Lincoln
Savannah
Susquehanna . . . .
Philippines
I.H.P.
8,400
45,000
15,800
5,600
10,900
21,000
6,800
90,000
7,400
6,940
7,200
45,000
9,000
9,000
8,500
8,500
2,500
9,520
4,200
Gross
Tonnage.
13,102*
19,361*
22,621*
9,835*
16,339*
25,570*
10,771*
64,282*
9,410*
8,312*
10,984*
19,603*
10,983*
10,893*
18,072*
18,168*
4,424t
10,058*
10,924t
• Transport.
t Repair ship.
X Shipping Bd.
first of all to the solenoid A, Fig. 77, which may be termed the brains of the apparatus.
The plunger of the solenoid is furnished at its upper extremity with a graphite piston
which works in a dashpot B, and so controls the motions of the plunger that hunting
is prevented. From the solenoid connection is made to the right-hand side of a re-
sistance C and from the left-hand side of the latter through the ammeter D to the
opposite terminal of the plug switch E to that occupied by the positive lead. The
resistance C consists of a series of carbon plates which are plain on one side and pro-
vided with numerous regularly placed projections, carefully ground to the same height,
on the other. The amount of resistance offered to the passage of current through this
pack of carbon plates can be varied by the amount of jressure put upon them by
means of the lever F^ which is pivoted at F and is rocked up and down on that point
by the movements of the plunger in the solenoid. If the current in the welding circuit
tend to increase beyond a predetermined value, then the plunger, and with it the
lever F^, are raised, with the result that the pressure on the carbon plates is relieved,
iSls 1,
^tjiJa:
114 ELECTRIC WELDING AND WELDING APPLIANCES
and in that way additional resistance inserted into the circuit. Then, if the other con-
dition^ remain the same, the current flowing in the circuit will fall, since the supply
voltage is constant. Conversely, if the current tends to fall below the required value,
the plunger and with it the lever F^ will also tend to fall, with the result that the
resistance of C is reduced by the compression of the carbon plates, and the current
flowing in the circuit will rise.
The quantity of current to be allowed to flow can be varied at will by what is
equivalent to running a weight backwards and forwards along the lever F, so that
the eflEort to raise it required of the solenoid is decreased or increased. As a matter
of fact, instead of a weight, the required effects are actually produced by decreasing
or increasing the tension on two coiled phosphor-bronze springs, the front of which,
G, is clearly shown in the engraving, that at the rear being hidden by its companion
in front. These two springs are connected to two small roller trolleys, one of which
can travel on the top of the lever F^, while the other impinges on the lower edge of
the fixed inclined guide H. It will be readily understood that since the guide H is
inclined downwards from the resistance C, the further the springs G are away from
C the greater will be the effort required of the solenoid to lift the lever F^ and hence
to reduce the pressure on the carbon plates. It follow^, therefore, that the greater
the distance of the springs G from C, the larger the current will be before the solenoid
will begin to take control. Conversely, the nearer the springs G are to C, the less the
effort required of the solenoid and the smaller the current flowing in the circuit before
the solenoid begins to act. Hence, by varying the position of the springs G, the exact
working current can be arranged for before operations commence. For the initial
adjustment of the carbon plates there is a screwed bolt at the left-hand side. This
bolt, however, will only require to be used for initial adjustment, and not in ordinary
working.
In some forms of the Wilson equipment this adjustment of the desired working
pressure on the carbon plates is effected by a hand wheel and screw, but in the equip-
ment which we saw, and which is shown in Fig. 77, the screw J, which passes through
a threaded member forming an integral part of the spring-carrying trolley that travels
on the top of the lever F^, can be revolved in one direction or the other by the revolu-
tion, in one direction or the other, of the small vertical spindle motor K. The advantage
of the latter arrangement is that if the operator finds on commencing to work that the
current flowing in his arc is either in excess of or smaller than the quantity required
to do the work to the best advantage — ^and he becomes aware of the ruling conditions
by the aspect of the work in progress — he can either decrease or increase it at will
by moving the motor control switch — see Fig. 78 — either to one side or the other.
The switch may be arranged so as to be portable and to be carried from one place to
another, so that the required alteration in the working conditions can be made without
the operator having to make a special journey to the control board for the purpose.
It may be added that there is a post G^ rising vertically from the trolley running on
the Isver F, which can engage with and can open two carbon block switches, which are
normally kept closed by spring action. One of these switches is arranged to be opened
at one end of the travel of the trolley, and the other at the other, so that if the trolley
should tend to overrun its travel in one direction or the other the circuit of the motor
K is opened.
In actual operation the movements of the plunger in the solenoid, and hence of
the lever F^, are not large, and the pointer of the ammeter keeps remarkably constant.
Still, there is a continuous and quite clearly visible compression and decompression
of the carbon blocks with the variation of the arc at the weld. All that happens if
THE PI^STIC-ARC WELDING SYSTEM 115
the electrode is kept on the work is that the resistance C gets hot, and would un-
doubtedly burn if the short circuit were continued long enough ; but we understand
that no damage would be done to the generator, since the resistance offered by the
carbon plates would be enough to preclude the passage of a current sufficiently heavy
to injure the machine.
We mentioned earlier in this chapter that the initial voltage was 37. In some
equipments at work in the United States the initial voltage is some two volts lower
than that. In the equipment that we inspected the voltage drop across the resistance
when welding was being performed was about 20. Hence for maintaining the arc and
for overcoming the resistance in the leads and solenoid there was only available 17
volts, and that is all that is required. The electrode being employed when we saw the
plant in operation was plain iron wire about ^^^ in. in diameter. It was not coated,
nor was flux of 'any kind employed. The work being done was, to all appearances,
excellent, and from tests, the data of which were shown to us, there is no doubt that
the system is capable of doing work of the very highest quality, the consequence,
it is explained, of having the current " just right " for each particular operation, and
of the ability to adjust it to the desired quantity without difficulty. The critical heat
at which the particular metal being welded should be fused is thus kept constant
at the arc, and there are neither voids nor burning. With an electrode of the size
mentioned — f^ in. — we are informed that the amount of metal deposited by One operator
per hour with a heat value of from 90 to 140 amperes at from 35 to 40 volts ranges
from I lb. to as much as 2J lb. to 3 lb., the average being about 1 J lb. per hour, the
actual quantity depending on the character of the work being carried out. Further-
more, we gather that the number of lineal feet that may be welded by one welder
ranges from 1^ ft. on | in. plate, with a liberal overlap of metal, to as much as 10 ft.
per hour on J in. stock, with no extra metal applied, a safe average being probably
about 4 ft. per hour. The results of tests which have been shown to us demonstrate
that the average tensile strength per square inch at the weld arrived at with eleven
specimens having an area of 0.628 square inch, the weld being planed flush with the
plate, was 54,700 lb., the elongation in 2 in. averaging 7.67 per cent. Nine specimens
having an area of 0.572 square inch gave 56,700 lb. as tensile strength and 10.0 per
cent, elongation in 2 in., while eleven further specimens having an area of 0.595 square
inch gave 58,900 lb. and 7.53 per cent, respectively, the figures being avei*age in all
cases. These results were obtained by taking a rectangular boiler plate 18 in. by 20 in.
of known tensile strength, cutting through the centre the long way and welding with,
a quality of wire suitable for the purpose. The plates were then cut into test pieces
1| in. wide and tested in the regular way after the welds had been planed flush on
both sides. It is claimed that welds made by the Plastic-arc system will stand much
more in the way of twisting and bending than will welds made by any other system.
The Wilson system was in the first instance, and long before it was employed for
ship repairs, developed for railway work. A very large volume of railway repair work
has been done by arc welding in the United. States for a good many years past, and has
been found to be convenient, effective and cheap. As an example of the class of job
which is frequently met with, we may mention cracked locomotive frames. Wrought
steel is largely used for locomotive frames in the United States, and it has been found
that when cracks develop in them the damage can readily be repaired by electric
welding.- The engraving, Fig. 79, shows a broken frame of engine No. 1653 of the
Grand Trunk Railway in process of being repaired by the Plastic-arc system at Strat-
ford, Ontario. The method employed is to cut away the metal, as shown, on each
side of the frame in the neighbourhood of the crack by means of pneumatic hammers.
116 ELECTRIC WELDING AND WELDING APPLIANCES
The space left by the material cut away is then filled by a piece B of metal
identical with the metal of the frame and square in ctobb section, and with two
. opposite comers matching with the V-shaped ends of the frame formed as a result
of the metal being cat away. Weldii^ is then commenced at the bottoms of the V- '
shaped cavities formed on each side of the frame, as shown in Fig. 79, and the process
is continued until the cavities are filled up and their surfaces brought fiush with or
perhaps a little proud of the original surface of the frame, as shown in Fig. 80. Repairs
such as that just described are frequently carried out, and are found to be quite effec-
tive.
Figs. 79, 80.
Cracked LocomotiTe Frame— Early Stage and Final Appearance of Repair by Arc Welding
CHAPTER XVII
THE A.C. SYSTEM OF ARC WELDING
As has been pointed out in an earlier chapter, direct current is almost exclusively
used for arc welding in thia country. In the United States, however, alternating
current haa been employed somewhat extensively, with, so we are given to imderstand,
considerable success. A company known as The A.C. Cutting and Welding Company,
Limited, the offices of which are at 25-27 Theobalds Road, Holbom, London, W.C. 1,
has recently been formed to introduce into this country the machine and methods of
on American firm. The machine, as the name of the company suggests, works with
alternating current, and for alternating current, at any rate if used with its machine,
the company claims numerous advantages. We may perhaps enumerate these claims
Fio. 8).— The A.C. Electric Welding and Cutting Mwhine.
before going on to describe the machine itself. First, there are low cost of operation
and no maintenance chiirges. In this connection it is pointed out that the A.C.
apparatus has no constantly moving parts, and that there is nothing, except accidental
mechanical injury or abuse, to prevent its lasting indefinitely. The apparatus, it is
stated, con8,umes approximately 0-15 kilowatt at a power factor of 65 per cent, when
not in actual operation, and when working will deposit a pound of metal for from 1 to 2
kUowatt'hours of energy. Then there is low cost of machine and wiring. On the first
portion of this claim we make no comment, but as concerns the second portion it may
be said that the distribution wiring is on the high-voltage side and that only small-
sized wires are required as compared, say, with a direct-current system using a motor
118
ELECTRIC WELDING AND WELDING APPLIANCES
generator in which the distribution cables to the arc welders are necessarily of large
cross section. The A.C. machine can be taken right up to the work, so that only quite
short welding-circuit cables are required.
Single PhdSe
One mschlne on
one ph^se ^tphtse
Two machines on 2 ph^se
One machine serosa
outers of Zphdse
te • 141 not
vo/ts^i
fmem/c^e
One madiine 0n3 phsse ^efta, «
Three machines on 3 phase deita
One machine on 3 phase star
*Thc Enoinccr"
One machine connecte<f to neutral
or 3 phase star-, voftaqe'SUotUne
voltage
Three phase star' 2 machines to neutral
'2 across regular power phases
Three phase star^ 3 machines ha/anced
en outers
Three phsse'4mre sysiem-S machines teneuUml^S across outers-'^il 6a fenced
Swain ^
Fia. 82. — Methods of Connecting up the A.C. Machinefl with Different Tjpes of Circuits.
A third claim made for the A.C. mjLchine is that with it there is greater speed of
deposition of the electrode metal than with other systems, and that no chipping or
brushing of the work is necessary. The company maintains that alternating current
THE A.C. SYSTEM OF ARC WELDING 119
provides a faster speed of welding than direct current when the electrode in the latter
case is negative, because with the electrode negative approximately 60 per cent, of
the heat is in the work, whereas with alternating current the heat is naturally divided
equally between the work and the electrode. It is admitted that direct current with
the electrode positive will provide a faster speed of welding, but it is urged that
generally it is " too fast to be of any use . . . unless the arc is closed in by very heavy
coating, so that the metal is enclosed in a viscous sleeve, or where the work is very
rough, such as filling in with a large electrode on a casting where strength is not
required." The following figures have been supplied to us of a test recently made with
direct-current and alternating-current machines. In each case in which conditions of
currents and voltage were strictly comparable it was found that alternating current
was from 20 to 30 per cent, faster than direct current. Thus at 1 50 amperes and 25 volts
4 lb. per hour of metal were deposited with alternating, as against 3 lb. per hour with
direct current. At 175 amperes and 25 volts 5 lb. per hour were deposited with
alternating current and 4 lb. per hour with direct current. As regards the contention
that no chipping or brushing is necessary, it is certainly true that with the A.C.
machine an arc can be struck from a rusty surface ; but we ;may say that the same
thing can be done with direct current.
A fourth claim for the A.C. system embodies " penetrtttion, smoothness and
absence of electrolytic corrosion." It is asserted that an alternating-current arc has a
penetrating power superior to that possessed by a direct-current arc, and that on that
account there is set up a molecular diffusion extending from J in. to f in. below the
surface of the work, so that its use is specially applicable to cast-iron welding. Again,
the surface of the metal deposited by the A.C. arc is said to be smoother than that of
metal deposited by direct-current arcs. Then with regard to electrolytic corrosion, it
is pointed out that whereas with direct-current welding there is the choice of making
the electrode either positive or negative, so that in either case there is a liability of the
formation of a voltage couple with consequent electrolytic corrosion, especially in damp
places, with alternating-current welding that liability is eliminated, as is also the chance
of the deposition of dross in the weldj as may happen when the electrode is negative.
Finally, the claim is made that the A.C. machine is more portable than any other
and that the system is very flexible. It is pointed out that (a) the apparatus can be
taken by two men exactly where it is required ; (6) the system is not tied down to a
certain number of machines or certain positions ; (c) the system operates as efficiently
with one machine running as with a few or a great many ; and (d) the machine, having
no continually moving parts, will work in any position.
Having set out the claims made for the system and apparatus, let us now con-
sider the apparatus itself. Its outward appearance is shown in the engraving.
Fig. 81. It consists of an oak box with louvred ends for ventilation, and with four
arms like those of old-fashioned Sedan chairs for carrying purposes. As to the internal
arrangements of the box, beyond the statement that they consist principally of a
specially wound transformer the company prefers at the moment to give no definite
particulars. All that we know for certain, therefore, is that the transformer has certain
tappings, which will be again referred to later ; that there is a flux diverter, by means
of which fine adjustments in the welding circuit are obtained ; and that the box also
contains an electrically driven blower, the purpose of which is, by circulating a current
of air through them, to keep the windings cool, and which absorbs some 60 watts. The
complete apparatus is said to be weather-proof, so that it can be used out of doors as
well as under cover, and skids are provided to facilitate movement of the box. The
louvred openings are provided with fine-mesh screens.
120 ELECTRIC WELDING AND WEIJ)ING APPLIANCES
The primary leads are led out from the side of the box through insulated bushes.
There are in all eight secondary plugs. They are arranged at one end of l^e box, and
are motmted on a slate bed protected by an oak fronting. The plugs are split so as to
make firm contact with the sockets at the ends of the welding leads. The eight welding
tap plugs provide adjustment for various types of welding or for different sizes of
electrode, any required adjustment within the limits of the machine being made by
taking a socket off one plug and putting it on another, no other means of switching
b^g necessary. The plugs may, in fact, be considered as being the means of bringing
about what may be called the coarse adjustment of the welding circuit. The flux
diverter, which is manipulated by the small hand wheel seen at the top of the box, and
the movement of which can be observed through a circular glass window, is for fine
adjustment after correct conditions have been roughly obtained by means of the plugs.
It is explained, too, that the flux diverter also determines the depth of the penetrative
effect of the arc — that is to say, whether"the metal will be sunk in as in sealing or added
on as in padding. The flux diverter handle ia provided with an indicator dial to
facilitate resetting when repetition work is being carried out.
It will be observed that there are six primary leads. Only two are actually
employed when the machines are at work, the others being carefully insulated, but the
Fig. 83.— The A.C. Electrode Holder.
Fig. 84.— The Holder Gripped to Eeleiwe Electrode.
three sets are provided so as to enable the apparatus to be used on circuits the voltage
of which is below the standard voltage for which the machine is intended. Moreover,
should the supply voltage be higher than the voltage for the highest set of tappings on
the primary, proper regulation can still be obtained by variation of the secondary plugs.
The range of primary voltage with which any one apparatus can be successfully
operated is therefore fairly wide. We return to this question later. Shifting the
secondary leads on to plugs from left to right on either side of the lamp in the centre
gives more heat in the weld. The function of the lamp, it may be explained, is to take
up the " kick " of the arc when the circuit is opened, and any 1 10-volt lamp is suitable
THE A.C. SYSTEM OF ARC WEJ.DING
121
for the purpose. The^lamp also gives indication when the machine is ready for work.
The A.C. machines are made in five sizes as follows : —
Tyi)e.
Range In welding.
Weisht.
Efficiency.
Amperes.
Per cent.
L.W. . .
.. 40 to 110
250-300
80
W.
.. 75 to 175
300-350
80
C.W
.. 100 to 350
350-400
80
H.C.G. ...
.. 300 to 650
400-^00
85
E.C.G. . .
. . 500 to 1200
600-800
90
The weights vary accordmg to the periodicities for which the transformers are wound.
. The machine can be wound for any voltage, but it is not considered good practice to
have a primary voltage in excess of 650. The machines are made as ordinarily wound
for single phase for any voltage or frequency, but if occasion requires it they can be
made for two or three-phase current, the power being taken from a two or three-
phase circuit balanced on each phase, the welding circuit, of course, consisting of only
two wires. The company informs us, however, that experience has taught it not to
recommend these polyphase machines, as they cost much more and weigh much more,
so that portability is lost with no attendant advantage of any kind. The diagram,
Fig. 82, is interesting, as showing the methods of connecting the machine to various
types of circuit.
The standard machines are wound for one voltage only, such as 110, 220, 440, etc. ;
but by reason of the means for connecting up the primary which are provided, and to
which we have already referred, the 110-volt primary circuit can be 100, 105, or 110 ;
the 220-volt primary circuit can be 200, 210, or 220 ; and the 440-volt primary circuit
can be 400, 420, or 440. These figures correspond to 5 and 10 per cent, low to the
nominated voltage. The secondary plugs provide a further range of 5 and 10 per cent,
high.
The power factor of the machine in welding is given as varying from 45 to 66 per
cent., a fair average being 55 per cent., which means that the kilovolt-amperage
required is approximately twice the kilowatts paid for. It is claimed that the load
factor with the machine may be as high as 75 per cent, on the average, since there is no
necessity to chip slag. Taking a power factor of 50 per cent, and a load factor of
75 per cent., the cost of one machine per hour with energy at IJd. per kilowatt-hour
is said to work out at less than 4d. In cutting, the power factor is so much higher
and the load factor so much lower that the average demand in a given time is the same
as when welding. The demand of the machine for the heaviest type of welding is
said to be 5 kilowatts, and for cutting 10 kilowatts.
In discussing the machine with the company's representatives emphasis was laid
on the following points : '' A fundamental feature in all arc welding machines should
be that a constant rate of heat should be automatically given out at the terminals.
Constant rate of heat means constant energy, or, in other words, constant watts. I'his
condition is brought about in our special transformer by a careful balance of the
secondary and primary windings, so that as the voltage tends to increase, owing, say,
to the arc lengthening or because of oil slag being in the path of the arc, the current
tends to diminish and vice versa, so that energy is delivered at an approximately
constant rate.
**A fundamental essential for good welding is that a short arc be held. This
condition is obtained in our machine by the swinging in and out of the voltage phase
relations of three voltages in series in the secondary winding of the transformer. Such
adjustment can be made that any short length arc can be held, and, when once set,
the adjustment can be locked so that it is impossible for a longer arc to be drawn than
122 ELECTRIC WELDING AND WELDING APPLIANCES
the fixed maximum. This company considers it as beyond argument that a short
arc is desirable in every case, for there is then less oxidation and nitrogenisation in the
erater and less radiation than with a long arc, while there is more certainty of the
electrode metal being deposited into the crater.
" We are able to hold an A.C. arc with 31 volts open circuit, although in practice,
because of line drop, poor contact, and various other reasons, we actually give more
than that, taps on the machine providing different voltages, both essential — ^for keep-
ing the arc going — and * kick ' voltages for different types of electrode and arc.
*'In addition to the transformer supplying all these requirements automatically
without continually moving parts, it further renders itself harm-proof when the
secondary terminals are short-circuited, in that the voltage drops to zero with a current
which can be adjusted to be less or greater than normal full-load current. As a matter
of fact, we adjust it for slightly in excess of that current so that slightly greater heat
is allowed for getting started.
** The one characteristic of our machine which is not shared by self -regulating
direct-current sets, which embody much the same characteristics of constant rate of
energy in the welding circuit, is that each voltage can be changed — both * essential '
and * kick ' — ^without changing the current, whereas i^ith direct-current sets change in
the voltage causes a corresponding change in the current."
We have not, ourselves, seen any tests carried out on welds made by this apparatus,
but we are informed that it will weld pieces which will bend flat on themselves — the
bend being in the weld — and which in a twisting test may be twisted through two
complete revolutions before tearing.
The A.C. machine can be used with any type of electrode — bare wire, flux-coated,
gaseous flux-coated, carbon, or graphite. The particular form of electrode holder or
welding handle, as the company prefers to call it, recommended is illustrated in Figs.
S3 and 84. It consists of a spring grip insulated holder, the metal portion of which is
composed of a metal which is not affected by the heat of the arc. It enables all types
of electrodes to be gripped at any desired angle without the necessity of keeping
pressure on either handle. On a slight squeeze being given to the holder, as seen in
Fig. 84, the stub end of a used electrode may be got rid of and a fresh electrode inserted.
The current is led to the electrode through both halves of the handle equally. The
flexible leads are brazed into the handle so that they become part and parcel of it.
INDEX
Abell, Mr. Westcott Stile, 97
A.C. Cutting and Welding Co., Ltd., The, 117
Electrode Holder, The, 120, 122
Machines, Methods of Connecting up with
different Types of Circuits, 118, 121
Acetylene Welding, 2, 19
" Added Thickness,*' 89
Admiralty Authorities, The, 6, 13
Aluminium, 15, 33
for Flux for Electric WeJding, 33
American Bureau of Steam Engineering, The,
111
American Duplex " Spot " Welder, Large, 81
Electrical Engineers, Listitute of, 71
" Spot " Welders for Ship Work, 80
Andrews, Mr. W. S. (American Genercd Electric
Co.), 74
A 1 Automatic Switch, 91
" Butt " Welder, 93
Manufacturing Co., Ltd., 89 et seq,
"Spot *' Welders, 90
Apparatus for Arc Welding, Machines and,
49 et aeq.
Ard between Two Electrodes:, Welding by means
of, 3
Arc, Crater of, Absorption of Oxygen by, 6
Effect of, on Human Frame, 4
Introduction of Gas into (Benaidos), 12
Positive Crater of. Temperature of, 4
Process, The Benardoe Carbon-, 8, 20
Projected by Electro-magnet, 3
The Plastic-, Welding System, 108 et seq.
Use of for Making Holes (Benardos), 11
Arc Welding, 1 et aeq., 8 et seq,, 33, 49, 65, 108, 1 17
At a Steel Barrel Works, 19 e^ aeq.
Company, Ltd., The British, 49
Arc Welding Equipment, Self-contained (The
British Westinghouse), 49 et seq.
Arc Welding Equipment on Motor Lorry
(British Westinghouse), 50
Arc Welding Equipments, 50, 54, 65
Arc Welding, Flux for, 5
Arc Welding, Generator for (British Westing-
house), 51
Arc Welding, Glass Screens for Protection while,
5, 20, 72
Arc Welding, Helmet for, 4, 5
Arc Welding, Loss in Steadying Resistemce
during, 52
Arc Welding, Machines and Apparatus for, 49
et 9eq.
Arc Welding, Motor Generator for (Crompton),
70,73
Arc Welding, Poliffity of Electrodes for, 2
Precautions to be tstken when, 4
Screens for Use when, 5, 20, 71
Arc Welding, Self-regulating Generators for,
51, 53 et seq,, 62, 63, 64
Arc Welding Set (Lancashire Dynamo and
Motor Co., Ltd.), 56
Arc Welding Set, Portable (J. H. Hohnes), 65, 66
Arc Welding Set, Self-contained (Crompton), 72
Arc Welding, SpecisJ Appliances Necessary
for, 3
Armour Plate, Formation of, by Electric
Welding (Benardos), 12
Asbestos, Blue, as Flux-forming coating for
Electrodes, 33
Attachments, "Butt" Welding (Al Manu-
facturing Co.), 89, 94
Attachments, " Seam " Welding (A 1 Manu-
facturing Co.), 89, 95
B
" Bad Metal," 6
Bakelite, 81
Balancer Set, ** Constant-energy," Electrical
Connections of, 63
Bafe Metal Electrodes, 3, 5, 71
Barge, Electrically-welded, 5
Barrel Co., Ltd., The Steel (Uxbridge), 19 et aeq.,
84 et seq.
Barrel, Steel, Description of Making, 21
Works, Arc Welding at a Steel, 19
Benardos, Nicholas de, 1 et seq., 8, 9, 20
and Olszewski Patent, 8 et seq.
Carbon Arc Process, 8 et seq.
Electrode Holders, 8 et seq.
Machines for Arc Welding, 10 et seq.
Bench Work, " Spot " Welder for (" Ponteleo "),
30
BlockE, Radial Electrode-, "Butt" Welder
with, 76, 77
Blow-holes, The Filling up of, 36
Blue Asbestos, as Flux-forming coating for
Electrodes, 33
Bonner, Mr. W. T. (Chester Shipbuilding Co.,
U.S.A.), 100
Borax used as a Flux in Brazing, 29
Bowling Iron Co., The, 3
Brass, Welding, 15
Brazing Collars on Tubes, Meu^hine for, 28
124
INDEX
Bridge Welding (Pontelec), 27
British Electric Plant Ck)., Ltd., 49
British Insulated & Helsby Cables Ltd. (B.I.W.),
39 ei seq.
B.I.W. R^istance Welders, 39 et seq.
" Seam " Welders, 45, 46
" Spot " Welders, 47, 48
Wire Welders, 39
British Westinghouse Electric & Manufacturing
Co., Ltd., 49
Bruce Peebles & Co., Ltd., 49
Bubbles, Gas, in Electric Welds, 6
Burd, Rear Admiral, U.S.N., 111
Bureau of Steam Engineering, The American,
111
" Butt " Welder (Electric Welding Co., Ltd.), 79
'* Butt " Welder for Miscellaneous Repair Work
(Electric Welding Co., Ltd.), 77
" Butt " Welder for Hoops, Rings, etc. (Electric
Welding Co., Ltd.), 79
" Butt " Welder for Hoops, Rods, etc. (Electric
Welding Co., Ltd.), 76, 76
" Butt " Welder for Tyres (Pontelec), 31,
" Butt " Welders (Al Manufacturing Co., Ltd.),
89 elaeq.
" Butt " Welders (B.I.W.), 39 et seq.
*• Butt " Welders (Electric Welding Co., Ltd.),
75 et aeq,
•* Butt " Welding, 2, 17. 31. 39 et aeq.
"Butt" Welding Attachments (A 1 Manu-
facturing Co., Ltd.), 89, 94
" Butt " Welding of T^res, Diagram Showing
Principle of, 17
Caldwell, Capt. (afterwards Major) James,
4, 6, 99 et aeq.
Caps for Electrodes of Large Welders, 83
Candy, Mr. A. M., 70, 71
Ceurbon, Alteration of Composition of Welded
Metal by, 2
Carbon Arc Process, The Benardos, 8
Welding, 6, 20
Carbon Arc Welding, First Employed Com-
mercially, 2, 3
Carbon Electrode Holder, 20
Electrodes, 2, 3
Carbon Electrodes Cored, 3
Cast Iron, Welding, 36
Chain-link-forming Machine, B.I.W., 41
Oiain-Hnk Welder, B.I.W., 43, 44
Chains, Machines for Making, B.I.W., 41 6/ aeq.
Clapper, Mr. J. B. (Standard Parts Co., Cleve-
land, Ohio), 14
Chester Shipbuilding Co., U.S.A., 100
Clutch, The Davies & Soewnes (Daysohms)
Electro-magnetic, b^ et aeq.
Coated Electrodes, 5 et aeq., 33 ei aeq.
Coating, Slag-forming, for Electrodes, 6
Coatings for Electrodes, aU not Slag-forming, 6
Collars, Machine for Brazing on Tubes, 28
Connections, Electric, for A.C. Welding
Machines with different Types of Circuits, 1 18
Connections, Electric, of British Westinghouse
Generator for Arc Welding, 51
Connections, Electric, of " Constant-energy "
Balancer Set, 63
Connections, Electric, of Davies & Soames
(Dayaphms) Differential Electro-magnetic
autch, 61, 62
Connections, Electric, of Lancashire Dyncimo &
Motor Co.'s Arc-welding Set, 57
Connections, Electric, of Large American
Duplex *' Spot '* Welder, 82
'* Constant-energy " Arc- welding Set, The, 62,
63
Continuous or " Point " Welding Machine
(Benardos), 11
** Continuous-union " Welding (Benardos), 9
Converter, Rotary, 96
Converter, Rotary Motor, 64
Cored Carbon Electrodes, 3
Coming Glass Co. of New York, 74
Crater of Positive Arc, Temperature of, 4
Crompton & Co., Ltd., 69 et aeq,
Crompton Self-contained Arc Welding Set, 72.
Crookes', The late Sir WilUam, Glass, 21, 72
Current Limits admissible with different sizes
of Quafei-arc Electrodes, 36
Current Variation in Arc Welding, 4, 22
Currents, Primary and Secondary, in Large
American Welders, 80
Cutting & Welding, The A.C. Co., 117
Cutting & Welding, The A.C. Co. Machine, 117
Cutting of Metals, The, 11, 37, 112
D
Damage to German Steamships, 108
Davies & Soame^ (Daysohms) Electro-magnetic
Differential Clutch, 58 et aeq,
Davies, Mr. Walter L., 68
Defects in Electric Welds, 6
de Meritens, 8
Device for Continuous or " Point " Welding
(Benardos), 11
Device for " Point " Welding (Benardos), 10
Dickinson, Mr. (The Bowling Iron Co.), 3
Differential Clutch, The Davies & Soames
(Daysohms) Electro-magnetic, 58 et aeq*
Disc Welding (" Pontelec "), 27
Disunion of Metals (Benardos), 11
Drills, Machine for Welding (B.I.W. ), 41 ,
Drums, Oil-, Manufacture of, by Electric
Welding, 84
Duplex "Spot^* Welder, Lckrge American, 81
Duplex " Spot " Welder, Large American,
Electriccd Arrangements of, 82
Dynamo & Motor. Co., Ltd.» The Lancctshire,
49, 56 e^ aeq.
E
Earthing Wire for Welding Machine, 91
Effect of the Arc on the Human Frame, 4
Elastic-limit of Electric Welds, 98
Electric Arc Welding, Benardos*, Machines for,
10, 11
Electric Forcje, Benardos', 10
Plant Co., Ltd., The British, 49
Welding Co , Ltd., The, 49, 75 et aeq.
Welding Co., Ltd., The Premier, 49
et aeq.
INDEX
125
Electric Welds, Defects in, 6
Examples of (Benardos), 9
Electrical Arrangements of Large American
Duplex " Spot " Welder, 82
Electrical Engineers, American Institute of, 71
Electrically-welded Barge, 6
Electro-magnetic Clutch, Da vies & Soames
(Daysohms), 58 et acq.
Electrode Holder, The A.C. Cutting & Welding
Co., Ltd., 120
Electrode Holder, The Benardos, 9
Electrode Holder, The Equipment & Engineer-
ing Co., 70, 73
Electrode Holder, The T. T. Heaton, 20
Holdeis, American, 70, 71
Electrodes, Bare Metal, 3, 5, 71
Benardos, 2, 3
Carbon, 2
Coatings for, not all Slag-forming, 6
Cored Carbon (Bencurdos), 3
Flux Coated, 5, 33
Graphite, 20, 71
Heat of Positive and Negative, 2
Kiellberg, 6
Electrode?, Mild Steel, suggested by Mr. T. T.
Heaton, 3
Electrodes, Polarity of in Arc Welding, 2
Quasi-arc, 35
Electrodes, Quasi-arc, Sizes for Sheet and Plate
Welding, 37
Electrodes, Slag-forming Coatings for, 6, 33
Slavianoff, 3
Emergency Fleet Corporation, The, U.S.A., 100
" Energy, Constant-", Arc Welding Set, 62, 63
Equipment and Engineering Co., The, 58, 64, 70
Eye Protection during Arc Welding, 71 et seq.
Filling up Blow-holes, 36
Fleet Corporation, The Emergency, U.S.A.,
100
Flux for Arc Welding, 5, 6, 22, 29
" Flux, Gaseous," I^ocess, 6
Forge, Electric, Benardos', 10
Formation of Armour Plate, Benardos' Sugges-
tion for, 12
Frame, Human, Effect of Arc on, 4
SpectcMsie-, Soldering Machine, 29
Franklin Institute of Philadelphia, 14
Friedrich der Oroaae, Damage to German Liner,
110, 111
G
Ga9 Bubbles in Electric Welds, 6
Gas, Litroduction into the Arc, proposed by
Benardos, 12
General Electric Co. of America, 74
Generating Set for Arc Welding r. Portable, J. H.
Holmes, 66, 66
Generators for Arc Welding, Self -regulating, 51,
53 et seq., 62, 70
German Steamships in America, Damage to by
Crews, 108
Glass, Coloured, for Plx>tecting the Eyes, 12, 20,
72
Glass, Crookes', 21, 72
Glass, Gold-plated, for Eye-protection during
Arc Welding, 74
Glass, " Safety," for Arc Welding, 72, 73, 74
Screens for Protecting the Eyes, 11, 20,
72, 73
Grand Trunk Railway, Repairs on, 115
Graphite Electrodes, 20, 71
H
Hand-operated Welder (Electric Welding Co.),
77, 79
Heaton, Mr. T. T., 19, 20, 21, 84
Helmet for Arc Welding, 4, 5
Holder, Electrode, American, 70, 71
The A.C., 120
The Benardos, 9
Holder, Electrode, The Equipment and Engin-
eering Co., 73
Holder, Electrode, The T. T. Heaton, 20
Holmes, J. H., & Co., 49, 65 et seq.
Hoops, Rings, etc., " Butt " Welder for
(Electric Welding Co.), 78, 79
Human Frame, Effect of Arc on, 4
Huron, S.S. (ex-German Friedrich der Grosae),
Damage to. Ill
Hydraulic Pressure for Consolidating Welds, 75
Iron, Welding Cast, 36
Jessop, Capt. E. P. (U.S.N.), 111
Jevons, Mr. A., 25
Jews' Harp Welder (Elihu Thomson), 14
Joint, Welded-riveted, 35
Joints, Welded and Riveted, Comparative
Strength of, 101
K
Kaiser Wilhelm II, German Liner, Damage to,
110
Kjellberg, Coated Electrode, 6
" Gaseous-flux " Process, 6
Koester, Capt. O. W. (American Bureau of
Steam Engineering), 111
Lancashire Dvnamo and Motor Co., Ltd., 49,
56, 57
Large ** Spot " Welders (American General
Electric Co.), 78, 80 et seq.
Large "Spot " Welding Machine, A (Pontelec),
103
Line Welding, 2
Link Welder, Chain (B.I.W.), 43, 44
Lloyd & Lloyd, Ltd., 3
Lloyd's Register, 1, 97
Lloyd's Register, Tentative Regulations for
Electric Welding, 97
Locomotive Frame, Cracked, Repair of, 116
126
INDEX
Lorry, Motor, Arc Welding Equipments
(Til ling-Stevens), 65 et seq.
Lorry, Motor, British Westinghouse Arc Weld-
ing Equipment on, 49, 60
Loss in Steadjong Resistances During Arc
Welding, 52
M
Machine, A Large British " Spot " Welding, 103
Machine, Arc Welding (Benardos), 3, 4
Machine, Chain-link-forming (B.I.W.)f 41
Machine for Brazing Collars on Tubes (Pontelec),
28
Machine for Soldering Spectacle-frames (Pon-
telec), 20
Machine for Welding Drills (B.I.W.), 41
Manufacture of Chains, Machines for (B.I.W.)>
41 et aeq.
Marquand, Mr. H. S., 51
Mather & Piatt, Ltd., 49
Mavor & Coulson, Ltd., 49
Metal, " Non-arcing," 92
Metals, Cutting, by the Quasi-arc Process, 37
Metals, Separation or Disunion of, Benardos, 1 1
Mild Steel Electrodes suggested by Mr. T. T.
Heaton, 3
Miscellaneous Repair Work, ** Butt " Welder
for (Electric Welding Co.), 77
Modulus of Elasticity of Electric Welds, 98
Motor Lorry, Arc Welding Equipments (Tilling-
Stevens), 65 ei acq.
Motor Lorry, British Westinghouse Arc Welding
Equipment on, 49, 50
Motor Generators for Arc Welding, 4, 49 e< seq.,
70, 73
'Nassovia, German Liner, 108
Navy, U.S., Secretary of, 108, 111
Noble, Mr. P. O. (American General Electric
Co.), 62
O
Oil Drums, Manufacture of, by Resistance
Welding, 84
Oil Drums, Resistance Welders for the Memu-
facture of, 87
Olszewski, Benardos and. Patent of, 8, 20
Stanilaus, 8
Operators, Training of. Time taken in, 21, 89
Overhecki Welding, 36
Patent, Benardos and Olszewski, 8
Peebles, Bruce & Co., Ltd., 49
Peters, G. D. & Co., Ltd., Ill
Phoenix Dynamo Mcmufacturing Co., Ltd., 25,
49
Plcustic-eirc Welding and Cutting Panel, 113
System, The, 108 et seq.
Plate and Sheet Welding, Sizes of Quasi-arc
Electrodes required for, 37
Plate Armour, Suggested Formation of,
Benardos, 12
Pocahontas, Repaired and Re-named German
Liner, 111
" Point-union," 9
Point, Multiple, Welding, 27
Polarity of Electrodes in Arc Welding, 2
Pontelec Machine for Brazing Collars on Tubes,
28
Pontelec Methods and Machines, 25
Resistance Welder, 26
" Spot " Welder, Large, 103
Typical, " Seam " Welder, 31, 32
Welding Patents, Ltd., 25 et seq,, 103,.
105
Pontelec Welding Processes, 27 et eeq.
Portable Welding Set (Crompton), 72
{J. H. Holmes), 65, 66
Portable Welding Set (Premier Electric Weld-
ing Co., 53 et 8eq,
Precautions to be taken when Arc Welding, 4
Premier Electric Welding Co., 49, 53 et seq.
Premier Welding Set in Cabin, 54
Pressure, Hydraulic, for Consolidating Welds, 75
Prinz Joachim, German Steamship, Damage to,
109
Prinzess Irene, German Steamship, Damage to,
109
Process, The Benardos Carbon Arc, 8
The Quasi-arc, 33 et seq.
Processes, Pontelec Welding, 27
Quasi- ABC Co., Ltd., 31 ef seq.
Electrodes, 35
Quasi-arc Electrodes, Current Limits Admis-
sible with Different Sizes of, 36
Quasi-arc Electrodes, Sizes Required for Sheet
and Plate Welding, 37
Quasi-arc Process, The, 33 et seq.
Cutting Metals by, 37
R
Radial Blocks, " Butt " Welder with, 76, 77
Railway, Grand Trunk, Repairs on, 115
Rawson, Woodhouse &, 25
Reactance in Arc Welding Circuit, 62
Rees-Ro turbo Manufacturing Co., Ltd., The, 49
Regulating, Self-, Generators for Arc Welding,
51, 53 et seq., 62, 70
Reinforcing Worn or Weak Work, 36
Repair Work, Miscellaneous, " Butt " Welder
for (Electric Welding Co.), 77
Repair Work, Railway, 115
Resistance Frame for Arc Welding (J. H.
Holmes), 65, 67
Resistance, Steadying, for Arc Welding, 3, 33,
34, 52, 65, 67
Resistance, Steadying, Loss in, 52
Resistance Welder, Caps for Electrodes of Large,
83
Resistance Welders (Al), 89 et seq.
(B.i.W.), 39 et seq.
Resistance Welders, Electric Welding Co., Ltd.,
15 et seq.
Resistance Welders for Oil-drum-making, 87
INDEX
127
Hesistcuice Welders, Leirge American " Spot,"
78, SOetseq.
Resistance Welders (Pontelec), 26 et seq., 103
Resistance Welding, 1, 14, 15, 25, 38, 39, 75, 89
Resistance Welding, Discovery of, by EHhu
Thomson, 14
Resistance Welding, Manufacture of Oil-drums
by, 84
Resistance Welding, Voltage for, 15
Ridge Welding (Pontelec), 28
Riveted and Welded Joints, Comparative
Strength of, 101
Rotary Converter (A 1 Manufacturing Co.), ®6
Rotsury Treucisformer (Equipment and Engineer-
ing Co.), 64
Roturbo Msuiufacturing Co., Ltd., The Rees, 49
S
«<
(C
((
SOBEEXS for Arc Welding, 5, 20, 71
Seam " Welder, Longitudinal (A 1), 89
Seam " Welder, Tyjiical Pontelec, 31, 32
Seam Welding, 3, 9, 17, 31, 46 et seq.
Welding Attachments (Al), 89, 95
Seam " Welding, Diagram Showing Principle
of, 17
" Seam " Welders, Examples of B.I.W., 45, 46
Self-contained Arc- welding Set (Crompton), 73
Self -regulating Generators for Arc Welding, 61,
53 et seq,, 62, 70
Separation or Disunion of Metals (Benardos), 11
Sheet and Plate Welding, Sizes of Quasi-arc
Electrodes required for, 37
Ship Work, American ** Spot " Welders for,
80
Skill, Operator's, Percentage Factor in Success-
ful Welding, 21
Slag-forming Coating for Electrodes, 6, 33
Slavianoff, 3
SoBjnes, Mr. Alfred, 58
Spectacle-frames, Machine for Soldering
(Pontelec), 29
" Spot " Welder (A 1 Manufacturing Co.), 90
for bench Work (Pontelec), 30
** Spot " Welder, Large American, for Ship
Work, 80
** Spot " Welder, Large American Duplex, 81
Typical Pontelec, 30
Welders (B.I.W. ), 47, 48
Welding, 2, 9, 16, 26, 27, 30, 31, 47,
et seq.y 78, 80 et eeq,, 90 et seq., 103 et seq.
*' Spot " Welding, Diagram Showing Principle
of, 16
" Spot '* Welding Machine, A Large British
(Pontelec), 103 et aeq.
Standard Parts Co., Cleveland, Ohio, 14
Steadying Resistance for Arc Welding, 3, 33, 34,
52, 65, 67
Steel Barrel Co., Ltd., Txbridge, 3, 19, 84
Works, Arc Welding at, 19
Steel Barrels, Description of making of by
Carbon Arc Welding, 21
Stewarts & Lloyd, Ltd., 3
Strength of Electric Welds, 97
Strips, '* Butt " Welder for (Electric Welding
Co.), 79
Strohmenger, Mr. Arthur Percy (Quetsi^arc), 33-
Switch, Automatic (" A 1 "), 91
Sjrstem, The Benardos Arc Welding, 8 et aeq.
The Plastic-arc Welding, 108
of Arc Welding, The A.C., 117
of Arc Welding, The Benardos, 8 et aeq.
Thomson Welding, Diagram of, 16
Temperature of Arc, 4
" Thickness, Added," 89
Thomson Electric Welding Co., The, 15
Ehhu, 1, 14
-Houston Electric Co., 14
Welding System, Dictgram of, 16
Tilling-Stevens, Ltd., 65 et aeq.
Traction Work, Rotary Transformer for Weld-
ing Work in, 64
Trckining of Welding Operators, Time taken in,.
21, 89
Transformer, Arrangement of, for Large
American " Spot " Welder, 81, 82
Transformer, Arrangement of, for Large
Pontelec " Spot " Welder, 106, 107
Transformer, Rotary, for Trewtion Arc Welding
Work, 64
Transformer, Static (Electric Welding Co.), 75
Transformers, Regulating, 80
Transformers, Static, 3, 14 e^ aeq.^ 16, 75, 80, 8U
82, 106
Tubes, " Butt " Welder for (Electric Welding
Co.), 75, 76
Tubes, Machine for Brazing Collars on
(Pontelec), 28
Typical Pontelec " Seam " Welder, 31, 32
" Spot " Welder, 30
Tyres, ** Butt " Welding of, Dictgram showing
principle of, 17
Ultimate Strength and Elongation of Welded
Material, 98
Union, Continuous-," Welding (Benardos), 9
Union, Point-," Welding (Benardos), 9
United States Shipping Board, 100
Uxbridge, Steel Barrel Co.'s Works at, 19, 84
Variation of Current in Arc Welding, 4
Vaterland, German Liner, Damage to, 108
Voltage for Arc Welding, 2, 24, 33, 61, 111, U5^
119
Voltage for Plastic-arc Welding, 111, 115
of A.C. Co.'s Machines, 121
W
Waahington, Oeorge, German Liner, Damage to,
109
Weld, Absorption of Oxygen by, 5
Welded Barge, Electrically, 5
and Riveted Joints, Comparison of, 101
Welded Material, Ultimate Strength euid
Elongation of, 98
128
INDEX
Welder, " Bait " (B.I.W.), 40, 43
Welder, " Butt/' for Tubes (Electric Welding
Co.), 75, 76
Welder, '' Butt," with Radial Welding Blocks
(Electric Welding Co.), 76, 77
Welder, Chain Link (B.I.W.), 43, 44
Hand-operated (Electric Welding Co.).
77,79
Welder, Jews' Harp (Elihu Thomson), 14
Large American Duplex ** Spot," 81
Resistance, T3rpical Pontelec, 26
Welder, " Spot " for Bench Work (Pontelec),
30
Welders, "Butt" (A 1 Manufacturing Co.,
Ltd.), 89
WeldeFB for Longitudinal Seams, 31, 32, 87
Welders, " Spot," for Ship Work, American, 80
for Steel barrel Mcmufetcture,
87
Resistance (Electric Welding Co.),
75 et seq.
Welders, " Seam " (B.I.W.), Examples of, 45, 46
" Spot " (A 1), 89, 90
(B.I.W.), 47, 48
Wire (B.I.W.), 39
Welding, Acetylene, 2, 19
Welding, Arc, 1 et seq., 14 el seq,, 19 e< seq., 33,
49, 65, 108 et seq„ 117
Welding, Arc, at a Steel Barrel Works, 19
Welding, Arc, Electrode Holders for, 9, 20, 70,
71, 73, 120
Welding, Arc, Helmet for, 4, 5
Welding, Arc, Machines and Apparatus for,
49 et seq.
Welding, Arc, Precautions to be tedcen when, 4
Welding, Arc, Set, The " Constant -Energy,"
62, 63
Welding, Arc, Set, Petrol-driven, Self-con-
tained (Crompton), 70
Welding, Arc, Set, Petrol-driven, Self-con-
tained (J. H. Holmes), 65, 66
Welding, Arc, Set (Lancashire Dynamo and
Motor Co.), 56, 57
Welding, Arc, Steadying Resistance for, 3, 33,
34, 52, 65, 67
Welding, Bridge, 27
Welding by Arc Struck between Two Elec-
trodes, 3
Welding, "Butt," 2, 17, 31, 39 et seq., 76
et seq., 89 et seq.
Welding, "Butt," of Tyres, 17, 31
Cast Iron, 36
Welding, " Continuous," or " Point," Machine
for (Benardos), 11
- Welding, " Continuous-union " (Benardos), 9
Disc (Pontelec), 27
Drills, Machine for (B.LW.), 41
Welding Hoops, Machine for (Electric Welding
Co.), 78, 79
Wekling, Line, 2
Machine, a Large British ** Spot," 103
Machines, Examples of Benardos, 10,
11
Midtiple-point (Pontelec), 27
Overhead, 36
Polarity of Electrodes in Arc, 2
" Point " Machine for (Benardos), 10
«' Point-union " (Benardos), 9
Portable Arc Plant (Plremier), 54, 55
Processes of (Pontelec), 27
Premier Electric Co., The, 49
Welding, Resistonce, 1, 14 et seq., 25, 39, 75
et seq., 84 et seq., S9 et seq
Welding, Resistance, Discovery of, by Elihu
Thomson, 14
WeWing, " Ridge " (Pontelec), 28
" Seam," 2, 9. 17, 32. U et seq.
Welding, " Seam," Diagram showing Principle
of, 16
Welding, Sheet and Plate, Sizes of Quasi-arc
Electrodes required for, 27
Welding, " Spot," 2, 9, 16, 26, 27, 30, 31, 47
ei seq., 78 et seq., 84 et seq., 89 et seq., 103
Welding, " Spot," Diagram showing principle
of, 16
Welding System, The Thomson, Diagram of, 16
The Electric Co., Ltd., 49
Thomson, System of, 14, 25
Welds, Electric, Defects in, 6
The Strength of , 97 et seq., 115
Gas Bubbles in, 6
Westinghouse Co., The British, Arc Welding
Equipment for Motor Lorry, 49, 50
Weyman, Mr. J. E., 65
Wilson System of Welding, List of Vessels
Repaired by, 112
Wilson System of Welding (Plastic-arc), 111
Wilson Welder and Metals Co., 108
Wire, Earthing, 91
Welders (B.I.W.), 39
Woodhouse & Rawson, 25
Zerener of Leipzig, 3
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